Hi,
I was wondering what other peoples experiences were of applying for and getting the extra 6 months of funding that some research councils seem to offer (certainly NERC do). There is some information at:-
http://www.nerc.ac.uk/funding/available/postgrad/studentinfo/extendphds.asp
but as the decisions are made at a departmental/institution level rather than centrally by NERC, I think the criteria as to whether you "qualify" or not is quite varied...