Just in case anyone is interested, or has the same problem... ie cannot access the forum via 3G whereas WiFi is fine, using hovercraft full of eels. (preferred option) or browser.
I contacted my mobile provider - The Phone Coop - a week ago and the issue still isn't resolved. They haven't washed their hands of me (yet) but they are scratching their heads as they haven't met this before. Admittedly they are a teeny weeny company compared to the likes of Orange.
So far we've tried;
- new SIM in old phone - no go
- replacement new SIM in new phone - no go
- signing up to another forum (
I only belong to this forum!) - failed with BikeRadar because they don't support Tapatalk
But worked with CycleChat - Chrome - no go
I did find the browser > Settings > Advanced > Website Settings by the way, but there doesn't appear to be an 'Add' option. Eh?
I'd really like this resolved because I like to catch up with the forum when I'm at work, especially on nights*
Cheers
Tigger
* before anyone gets on their soapbox... I can do what I want when I don't have a customer to see to. Well, within reason

Edited to change IE to just 'browser'