If it extracts a fired case, then the extractor and spring are OK. That is, unless as soon as the case clears the chamber it falls of the extractor. Then it might be you have a .303 extractor.
Try working the action quite smartly/ vigorously. If it still doesn't eject, then you have a drama. If I recall correctly, the 2a has its ejector on the LH mag lip, similar to the L8/L42a1.
There's an old thead devoted to pictures of the various mags that might show this feature.
Might just need a light tweaking of the top of the LH mag lip to function, but I never had a problem, even when using multiple mags whilst playing retro CQB.
The thread w/ pics (see post #23):
Amatuer's guide to Enfield magazines?? - Page 3 - Military Surplus Collectors Forums