Mailchimp App Groups Errors

Hi,

Having difficulty setting up integrating the interests feature using the Mailchimp app. An example of the code I am using for the interest selection is:

<perch:input id="interest_health" type="checkbox" class="filter__control" value="13918e80c7" label="Health" mailer="interests" />
<perch:input id="interest_sport" type="checkbox" class="filter__control" value="8a05a32db2" label="Sport" mailer="interests" />
<perch:input id="interest_careers" type="checkbox" class="filter__control" value="d67a9dbbf8" label="Careers" mailer="interests" />

The response when attemping to subscribe using the form is:

( ! ) Notice: Undefined index: interest_careers in /path/to/site/build/admin/addons/apps/perch_mailchimp/lib/PerchMailChimp_Subscribers.class.php on line 54

Perch diagnostics:

PERCH INFORMATION

Perch: 2.8.29
Production mode: Development (10)
Installed apps: content (2.8.29), assets (2.8.29), categories (2.8.29), perch_blog (5.0), perch_forms (1.8.3), jw_translations (1), perch_mailchimp (3.0.1)
DB driver: PDO
DB tables: perch2_blog_authors (1), perch2_blog_comments (0), perch2_blog_index (35), perch2_blog_posts (1), perch2_blog_posts_to_tags (0), perch2_blog_sections (1), perch2_blog_tags (0), perch2_blogs (1), perch2_categories (17), perch2_category_counts (1), perch2_category_sets (3), perch2_content_index (2657), perch2_content_items (160), perch2_content_regions (46), perch2_forms (3), perch2_forms_responses (20), perch2_mailchimp_campaigns (0), perch2_mailchimp_imports (0), perch2_mailchimp_lists (1), perch2_mailchimp_subscribers (1), perch2_mailchimp_subscriptions (1), perch2_mailchimp_webhooks (0), perch2_navigation (1), perch2_navigation_pages (3), perch2_page_templates (11), perch2_pages (16), perch2_resource_log (192), perch2_resource_tags (0), perch2_resources (20), perch2_resources_to_tags (0), perch2_settings (26), perch2_user_passwords (0), perch2_user_privileges (40), perch2_user_role_privileges (57), perch2_user_roles (4), perch2_users (1)
Users: 1
App runtimes:
<?php
    $apps_list = array(
        'content', 
        'categories',
        'jw_translations',
        'perch_blog',
        'perch_forms',
        'perch_mailchimp'
    );
Scheduled tasks for perch_blog: delete_spam_comments (1440 mins)
Scheduled tasks for perch_mailchimp: import_data (1 mins)
Editor plug-ins: markitup, redactor
H1: 3844c03a4eb94fd413aa0fa8ce32421d
L1: 800977a505b64cea582681715db6b54c
F1: 2edba60ed1f613d6dd804feb202456a2
headerColour: #21B2AB
content_singlePageEdit: 1
siteURL: /
hideBranding: 1
content_collapseList: 1
lang: en-gb
update_2.8.29: done
latest_version: 2.8.15
on_sale_version: 2.8.30
headerScheme: dark
dashboard: 0
hide_pwd_reset: 0
content_hideNonEditableRegions: 0
content_frontend_edit: 0
logoPath: /admin/resources/dream-big.png
perch_blog_update: 5.0.1
perch_blog_post_url: /your-life/article/{postSlug}
perch_blog_site_name:
perch_blog_slug_format: {postID}-{postTitle}
perch_blog_akismet_key:
perch_blog_max_spam_days: 0
perch_blog_comment_notify: 0
helpURL: mailto:design@rootstudio.co.uk
perch_mailchimp_api_key: XXXXXXXXXXXX
perch_mailchimp_campaign_url: /mailchimp/campaign/{campaignSlug}
perch_mailchimp_secret: c79b691
PERCH_DEVELOPMENT: 10
PERCH_STAGING: 50
PERCH_PRODUCTION: 100
PERCH_TZ: UTC
PERCH_EMAIL_FROM: james@rootstudio.co.uk
PERCH_EMAIL_FROM_NAME: James Wigger
PERCH_LOGINPATH: /admin
PERCH_PATH: /Users/James/Repositories/Social Change/dream-big-core-site/build/admin
PERCH_CORE: /Users/James/Repositories/Social Change/dream-big-core-site/build/admin/core
PERCH_RESFILEPATH: /Users/James/Repositories/Social Change/dream-big-core-site/build/admin/resources
PERCH_RESPATH: /admin/resources
PERCH_HTML5: 1
PERCH_DB_USERNAME: root
PERCH_DB_SERVER: localhost
PERCH_DB_DATABASE: dream_perch
PERCH_DB_PREFIX: perch2_
PERCH_YOUTUBE_API_KEY: AIzaSyCK7nvjlv1_6wl3_NmZvum0Tqo0mB4fBpc
PERCH_DEBUG: 1
PERCH_PRODUCTION_MODE: 10
PERCH_TRANSLATION_LANG: en-gb
PERCH_RUNWAY:
PERCH_ERROR_MODE: DIE
PERCH_DATE_LONG: %d %B %Y
PERCH_DATE_SHORT: %d %b %Y
PERCH_TIME_SHORT: %H:%M
PERCH_TIME_LONG: %H:%M:%S
PERCH_RUNWAY_ROUTED:
PERCH_STRONG_PASSWORDS:
PERCH_PREVIEW_ARG: preview
PERCH_TEMPLATE_PATH: /Users/James/Repositories/Social Change/dream-big-core-site/build/admin/templates
PERCH_DEFAULT_DOC: index.php
PERCH_DEFAULT_EXT: .php
PERCH_RWD:
PERCH_HTML_ENTITIES:
PERCH_SSL:
PERCH_STRIPSLASHES:
PERCH_PROGRESSIVE_FLUSH: 1
PERCH_PARANOID:
PERCH_FORCE_SECURE_COOKIES:
PERCH_PASSWORD_MIN_LENGTH: 6
PERCH_MAX_FAILED_LOGINS: 10
PERCH_AUTH_LOCKOUT_DURATION: 1 HOUR
PERCH_VERIFY_UPLOADS:
PERCH_AUTH_PLUGIN:
PERCH_DB_CHARSET: utf8
PERCH_DB_PORT:
PERCH_DB_SOCKET:
PERCH_SESSION_TIMEOUT_MINS: 20
HOSTING SETTINGS

PHP: 5.6.10
Zend: 2.6.0
OS: Darwin
SAPI: cgi-fcgi
Safe mode: not detected
MySQL client: mysqlnd 5.0.11-dev - 20120503 - $Id: 3c688b6bbc30d36af3ac34fdd4b7b5b787fe5555 $
MySQL server: 5.5.42
Free disk space: 409.15 GB
Extensions: Core, date, ereg, libxml, openssl, pcre, sqlite3, zlib, bcmath, bz2, calendar, ctype, curl, dom, hash, fileinfo, filter, ftp, gd, SPL, iconv, intl, json, ldap, mbstring, session, standard, mysqlnd, mysqli, PDO, pdo_mysql, pdo_sqlite, Phar, posix, readline, Reflection, mysql, SimpleXML, soap, sockets, exif, tokenizer, wddx, xml, xmlreader, xmlwriter, xsl, zip, cgi-fcgi, imap, gettext, mcrypt, yaz, pgsql, pdo_pgsql, xdebug
GD: Yes
ImageMagick: No
PHP max upload size: 32M
PHP max form post size: 32M
PHP memory limit: 128M
Total max uploadable file size: 32M
Resource folder writeable: Yes
Session timeout: 24 minutes
Native JSON: Yes
Filter functions: Yes
Transliteration functions: Yes
PHP_FCGI_CHILDREN: 4
PWD: /Applications/MAMP/fcgi-bin
PHP_FCGI_MAX_REQUESTS: 200
__CF_USER_TEXT_ENCODING: 0x1F5:0x0:0x0
ORIG_SCRIPT_NAME: /fcgi-bin/php5.6.10.fcgi
ORIG_PATH_TRANSLATED: /Users/James/Repositories/Social Change/dream-big-core-site/build/admin/core/settings/diagnostics/index.php
ORIG_PATH_INFO: /admin/core/settings/diagnostics/index.php
ORIG_SCRIPT_FILENAME: /Applications/MAMP/fcgi-bin/php5.6.10.fcgi
SCRIPT_NAME: /admin/core/settings/diagnostics/index.php
REQUEST_URI: /admin/core/settings/diagnostics/?extended
QUERY_STRING: extended
REQUEST_METHOD: GET
SERVER_PROTOCOL: HTTP/1.1
GATEWAY_INTERFACE: CGI/1.1
REDIRECT_URL: /admin/core/settings/diagnostics/index.php
REDIRECT_QUERY_STRING: extended
REMOTE_PORT: 64539
SCRIPT_FILENAME: /Users/James/Repositories/Social Change/dream-big-core-site/build/admin/core/settings/diagnostics/index.php
SERVER_ADMIN: you@example.com
DOCUMENT_ROOT: /Users/James/Repositories/Social Change/dream-big-core-site/build
REMOTE_ADDR: ::1
SERVER_PORT: 80
SERVER_ADDR: ::1
SERVER_NAME: dream-big.local
SERVER_SOFTWARE: Apache
PATH: /usr/bin:/bin:/usr/sbin:/sbin
HTTP_ACCEPT_ENCODING: gzip, deflate
HTTP_REFERER: https://dream-big.local/admin/core/settings/diagnostics/
HTTP_ACCEPT_LANGUAGE: en-us
HTTP_USER_AGENT: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/601.5.17 (KHTML, like Gecko) Version/9.1 Safari/601.5.17
HTTP_COOKIE: _ga=GA1.2.396239224.1464191517; PHPSESSID=3457975cf3f47b94f05527a07647a50a; __atuvc=9%7C25%2C0%7C26%2C24%7C27; __atuvs=577a56de30ee85e0017; cmsa=1
HTTP_CONNECTION: keep-alive
HTTP_ACCEPT: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
HTTP_HOST: dream-big.local
REDIRECT_STATUS: 200
REDIRECT_HANDLER: php-fastcgi
FCGI_ROLE: RESPONDER
PHP_SELF: /admin/core/settings/diagnostics/index.php
REQUEST_TIME_FLOAT: 1467639016.63
REQUEST_TIME: 1467639016
argc: 1

Is it not possible to use checkboxes for the interest selection?