Basket and login not working

Good morning,

I've been trying in vain to launch a Perch shop over the last few days on a clients preferred shared host. Unfortunately whilst we're running absolutely fine locally and on our own development server, running in the live environment simply will not work. My diagnostics aren't flagging anything missing in PHP which is obvious to me. I have a staging version of the site running here: https://staging.ecofriendlyshop.co.uk with debug mode on. When we try and add items to the basket or try and login nothing happens. I can't see any PHP errors or anything in the logs/debug but the debug seems a lot shorter in the live environment!

My guess here is that something to do with sessions is missing from the live environment but before I contact the hosts I could really do with a heads-up as to what I might need to be asking for as it's not immediately obvious.

Perch Runway: 3.0.14, PHP: 7.2.4, MySQL: mysqlnd 5.0.12-dev - 20150407 - $Id: 38fea24f2847fa7519001be390c98ae0acafe387 $, with PDO
Server OS: Linux, cgi-fcgi
Installed apps: content (3.0.14), assets (3.0.14), categories (3.0.14), perch_shop_orders (1.2.5), perch_shop_products (1.2.5), perch_shop (1.2.5), perch_members (1.6.2)
App runtimes: <?php $apps_list = [ 'perch_members', 'perch_shop' ];
PERCH_LOGINPATH: /admin
PERCH_PATH: /home/efriend1/staging.ecofriendlyshop.co.uk/admin
PERCH_CORE: /home/efriend1/staging.ecofriendlyshop.co.uk/admin/core
PERCH_RESFILEPATH: /home/efriend1/staging.ecofriendlyshop.co.uk/admin/resources
Image manipulation: GD
PHP limits: Max upload 2M, Max POST 8M, Memory: 32M, Total max file upload: 2M
F1: 3b606135b33e6a102526838f4152a807
Resource folder writeable: Yes
DOCUMENT_ROOT: /home/efriend1/staging.ecofriendlyshop.co.uk
HTTP_HOST: staging.ecofriendlyshop.co.uk
REQUEST_URI: /admin/core/settings/diagnostics/
SCRIPT_NAME: /admin/core/settings/diagnostics/index.php

There's also a PHP info file available: https://staging.ecofriendlyshop.co.uk/info.php

Any light you can shed on this would be appreciated as we're ready to launch we just can't seem to be able to push the button.

Thanks in advance, Lea.