If you’ve not asked gamstop to remove you from their system, you wont be able to join UK gambling sites. Theres a process they go through beforehand (I cant remember what because the first time I did it was a while ago). I’m on for 5 years this time and it was easy enough to get back onto. Give them a message and see if they can extend it for you.
You sound like you know what you have to do anyway, so I wish you the best with it ๐