I'd class it as broadly a 3rd section piece - but it is a little difficult to classify it so baldly, because the real difficulty to it lies in the middle movement, which is slow, sustained and quiet, and requires a band with real control to bring off perfectly. Quite a few 4th section bands will be able to play it well, with enough rehearsal time, whereas some 2nd section bands won't. If nothing else, rehearsing this movement cannot fail to enrich the band's tone/balance/togetherness.
And apart from all that, it's a lovely piece of music. I'd recommend that you do get it out and rehearse it, even if you decide not to contest with it.
Dave