Sorry, just been so foo*ed off with it all, and that looked easy on there!
It was a great deal tighter than that, I couldn't budge it like that and didn't want to force it in case there was more to it so took it to a garage.
Don't know what they did but I waited for 10 mins and it cost £20 so was happy enough with that.
I hope I don't have to replace another one......