Thanks for your help guys, knew I could count on you.
CAP 513 was the answer. One of the few things the CAA have produced that contains everything you need to know in one place! Some of Boeings proposals on this matter are a bit worrying especially as the FAA seem quite happy to accomodate them. For example the 777 now has a maximum ETOPS of 207 minutes. Could anyone feasibly see a flight crew being able to deal with a serious systems failure (or multiple systems failure) for roughly 3 1/2 hours? Can the aircraft realistically deal with a major systems failure for that long? Its good to see at the moment JAA won't be swayed by Boeing but can anyone see that lasting for long?