Markitup textarea toolbar missing after upgrade to Perch 2.8.2

I've just upgraded from (I think) Perch 2.3 to (definitely) Perch 2.8.2. I also upgraded blog and made the categories changes required in my blog templates. That's all fine but if I try to use blog (or any other textarea edit on standard pages) then the markitup editor toolbar is missing.

I notice in the Perch Update 2.8.2 page that I need to copy the 2.8.2 perch/addons/plugins/editors/markitup folder to replace my existing markitup folder - I have done this!

Usage in post.html looks like this:

<perch:blog id="postDescHTML" type="textarea" label="Post" order="2" editor="markitup" textile="true" size="xxl autowidth" required="true" />

<perch:blog id="excerpt" type="textarea" label="Excerpt" editor="markitup" textile="true" order="3" suppress="true" size="s" />

Any thoughts?

Here are my diagnostics...

Perch information

Perch: 2.8.2
Production mode: Production (100)
Installed apps: content (2.8.2), assets (2.8.2), categories (2.8.2), perch_blog (4.6), perch_forms (1.5), perch_backup (1.2), perch_twitter (3.1)
DB driver: PDO
DB tables: perch2_blog_authors, perch2_blog_categories, perch2_blog_comments, perch2_blog_index, perch2_blog_posts, perch2_blog_posts_to_categories, perch2_blog_posts_to_tags, perch2_blog_sections, perch2_blog_tags, perch2_categories, perch2_category_counts, perch2_category_sets, perch2_content_index, perch2_content_items, perch2_content_regions, perch2_forms, perch2_forms_responses, perch2_navigation, perch2_navigation_pages, perch2_page_templates, perch2_pages, perch2_resource_log, perch2_resource_tags, perch2_resources, perch2_resources_to_tags, perch2_scheduled_tasks, perch2_settings, perch2_twitter_settings, perch2_twitter_tweets, perch2_user_privileges, perch2_user_role_privileges, perch2_user_roles, perch2_users, perch_blog_categories, perch_blog_posts, perch_blog_posts_to_categories, perch_blog_posts_to_tags, perch_blog_tags, perch_contentItems, perch_forms, perch_forms_responses, perch_settings, perch_twitter_settings, perch_twitter_tweets, perch_users
Users: 3
App runtimes:

<?php
    include(PERCH_PATH.'/core/apps/content/runtime.php');
    include(PERCH_PATH.'/core/apps/categories/runtime.php');
    include(PERCH_PATH.'/addons/apps/perch_twitter/runtime.php');
    include(PERCH_PATH.'/addons/apps/perch_blog/runtime.php');
    include(PERCH_PATH.'/addons/apps/perch_forms/runtime.php');
?>

Scheduled tasks for perch_twitter: update_tweets (15 mins)
Scheduled tasks for perch_blog: delete_spam_comments (1440 mins)
Editor plug-ins: markitup
H1: 07660e1ce46d35bd135f87f5cae53fa6
L1: 97d35022ed9c279153cd478c85558135
headerColour: #ffffff
content_singlePageEdit: 1
helpURL:
siteURL: /
hideBranding: 1
content_collapseList: 1
lang: en-gb
latest_version: 2.7.10
headerLinkColour: #000000
logoPath: /admin/resources/logo-perch.png
linkColour: #333333
perch_blog_post_url: /blog/post.php?s={postSlug}
perch_backup_mysqldump_path:
editorMayDeleteRegions: 0
perch_forms_editorMayConfigure: 0
perch_forms_editorMayDelete: 0
perch_blog_editorMayManageCats: 0
perch_backup_admin_only: 0
headerScheme: light
perch_upgrade_v1_prefix: perch_
perch_blog_slug_format: %Y-%m-%d-{postTitle}
perch_blog_akismet_key:
dashboard: 0
content_hideNonEditableRegions: 0
update_2.1.3: done
perch_blog_comment_notify: 0
update_2.2.11: done
on_sale_version: 2.8.2
update_2.8.2: done
perch_blog_update: 5.0
PERCH_DEVELOPMENT: 10
PERCH_STAGING: 50
PERCH_PRODUCTION: 100
PERCH_DB_USERNAME: amodeowe_amodeo2
PERCH_DB_SERVER: localhost
PERCH_DB_DATABASE: amodeowe_amodeo2
PERCH_DB_PREFIX: perch2_
PERCH_EMAIL_FROM: nigel@amodeowebdesign.co.uk
PERCH_EMAIL_FROM_NAME: Nigel Harding
PERCH_LOGINPATH: /admin
PERCH_PATH: /home/amodeowe/public_html/admin
PERCH_CORE: /home/amodeowe/public_html/admin/core
PERCH_RESFILEPATH: /home/amodeowe/public_html/admin/resources
PERCH_RESPATH: /admin/resources
PERCH_HTML5: 1
PERCH_SCHEDULE_SECRET: amodeo123
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_DEBUG:
PERCH_PREVIEW_ARG: preview
PERCH_TEMPLATE_PATH: /home/amodeowe/public_html/admin/templates
PERCH_DEFAULT_DOC: index.php
PERCH_DEFAULT_EXT: .php
PERCH_PRODUCTION_MODE: 100
PERCH_RWD:
PERCH_HTML_ENTITIES:
PERCH_SSL:
PERCH_STRIPSLASHES:
PERCH_PROGRESSIVE_FLUSH: 1
PERCH_AUTH_PLUGIN:
PERCH_DB_CHARSET: utf8
PERCH_DB_PORT:
PERCH_DB_SOCKET:
PERCH_APPS_EDITOR_PLUGIN: markitup
PERCH_APPS_EDITOR_MARKUP_LANGUAGE: textile

Hosting settings

PHP: 5.4.33
Zend: 2.4.0
OS: Linux
SAPI: cgi-fcgi
Safe mode: not detected
MySQL client: mysqlnd 5.0.10 - 20111026 - $Id: c85105d7c6f7d70d609bb4c000257868a40840ab $
MySQL server: 5.6.23
Extensions: Core, date, ereg, libxml, openssl, pcre, sqlite3, zlib, bcmath, bz2, calendar, ctype, curl, dom, hash, filter, ftp, gd, gettext, SPL, iconv, session, json, mbstring, mcrypt, standard, mysql, mysqli, pgsql, posix, pspell, Reflection, mysqlnd, imap, SimpleXML, soap, sockets, exif, tidy, tokenizer, wddx, xml, xmlreader, xmlrpc, xmlwriter, xsl, zip, cgi-fcgi, PDO, pdo_sqlite, timezonedb, pdo_mysql, ionCube Loader, Zend Guard Loader
GD: Yes
ImageMagick: No
PHP max upload size: 20M
PHP max form post size: 20M
PHP memory limit: 128M
Total max uploadable file size: 20M
Resource folder writeable: Yes
Session timeout: 24 minutes
Native JSON: Yes
Filter functions: Yes
Transliteration functions: No
UNIQUE_ID: VQGwbVVcTjcACUk376IAAAAS
HTTP_USER_AGENT: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:36.0) Gecko/20100101 Firefox/36.0
SERVER_PORT: 80
HTTP_HOST: www.amodeowebdesign.co.uk
REDIRECT_HANDLER: application/x-httpd-php5
DOCUMENT_ROOT: /home/amodeowe/public_html
SCRIPT_FILENAME: /home/amodeowe/public_html/admin/core/settings/diagnostics/index.php
REQUEST_URI: /admin/core/settings/diagnostics/?extended
SCRIPT_NAME: /admin/core/settings/diagnostics/index.php
HTTP_CONNECTION: keep-alive
REMOTE_PORT: 52037
PATH: /usr/local/bin:/usr/bin:/bin
CONTEXT_PREFIX: /cgi-sys
PWD: /usr/local/cpanel/cgi-sys
SERVER_ADMIN: webmaster@amodeowebdesign.co.uk
REQUEST_SCHEME: http
REDIRECT_STATUS: 200
REDIRECT_QUERY_STRING: extended
HTTP_ACCEPT_LANGUAGE: en-US,en;q=0.5
HTTP_REFERER: https://www.amodeowebdesign.co.uk/admin/core/settings/diagnostics/
HTTP_ACCEPT: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
REMOTE_ADDR: 78.149.143.249
SERVER_NAME: www.amodeowebdesign.co.uk
SERVER_SOFTWARE: Apache
QUERY_STRING: extended
SERVER_ADDR: 85.92.78.62
GATEWAY_INTERFACE: CGI/1.1
SERVER_PROTOCOL: HTTP/1.1
HTTP_ACCEPT_ENCODING: gzip, deflate
REDIRECT_URL: /admin/core/settings/diagnostics/index.php
REQUEST_METHOD: GET
HTTP_COOKIE: __utma=90548490.2098638702.1415951174.1426149194.1426173514.26; __utmz=90548490.1425660481.20.2.utmcsr=t.co|utmccn=(referral)|utmcmd=referral|utmcct=/ATiNQqoOh1; cmsa=1; PHPSESSID=c15d63b59b7d98872b2663edf2698245; __utmc=90548490; __utmb=90548490.4.9.1426173519511; __utmt=1
CONTEXT_DOCUMENT_ROOT: /usr/local/cpanel/cgi-sys/
ORIG_SCRIPT_FILENAME: /usr/local/cpanel/cgi-sys/php5
ORIG_PATH_INFO: /admin/core/settings/diagnostics/index.php
ORIG_PATH_TRANSLATED: /home/amodeowe/public_html/admin/core/settings/diagnostics/index.php
ORIG_SCRIPT_NAME: /cgi-sys/php5
PHP_SELF: /admin/core/settings/diagnostics/index.php
REQUEST_TIME_FLOAT: 1426174061.36
REQUEST_TIME: 1426174061
argc: 1