I bought this game from Amazon UK but it arrived from Canada. Problem is while it plays on a UK PS3 the disc is region 1 USA so when i downloaded add ons like the Battle of Britain missions from the play station store they are incompatible with this version.
Answer is to download the game from the play station store via your PS3. Save £10 and it will automatically be compatible with any add ons you also download later from the same region store. I wasted my money.