I, along with scores of others, used GPS in mil ac as soon as it became clear the MOD and the 'old school' were not going to play. I also used an ipad in flight for mapping, GPS and flight pubs over a year ago. The iphone with memory map was invaluable on NVG Cat A(F) instructional sorties.
As long as the relatively simple trials process is undertaken, the use of an ipad in flight is easy to clear - it already is in the Puma.