I have a 2009 classic and I always have to pump the clutch once to guarantee a solid clunk into first. If I don't, it will commonly slip into neutral again. So I wouldn't be concerned. It has never slipped out of gear on me after a clutch pump and solid clunk.
Well I've never had it jump out of gear either. Just like you said, moklodge, pump it to solid clunk and its perfectly fine. Same with no pumping either. Sometimes it goes in fine but also sometimes goes back to neutral. Yikes warp! I will definitely double check the free play!
My "new" 2012 seems to go into first after being in neutral better if I "double clutch" it; but finding neutral is always very easy; and it's never jumped out of any gear.
Synchros do not work so well when they are not spinning. Mine also from day one will not fully engage 1st from neutral at a stop unless I led out the clutch and spin the input shaft. It really shouldn't be anything to worry about.