Hi,
Use Bristol GS. I do and it's got me through Mod 1 with 94% average. (Whether I'll average that in Mod 2 who knows!) PTC changed over to BGS recently too.
At the end of the day you read the book in Dublin but just go to Bristol for the Brush-up which is good (speaking from personal experience) and straight into the exams. You've got the online forum to ask q's, some people use it a lot like me, some not at all.
Given the exams seem to be little more than a tick in a box, this seems like the best way to do it.
And whether you do it in Dublin, London or the South Pole - it's work you put in that yields the result.
Nk
ps - I have no connection to BGS!