Sounds similar to my case. Had a bit of wheezness due to hayfever as a child. Didnt tell Cranwell on application got in but it came back to bite me a few years later.
However all I had to do was a bike excercise test at Peterborough to try and induce wheezing and it was ok. What have you got to lose. If you tell them they will say no if you dont they may catch you out and say no but there is a chance they will not pick it up and you get in.
Is it worth the risk I think so.