The truth of the matter is, if you didn't declare it, it's unlikely your AME would find out, unless you crashed into a house, or otherwise killed a few people with your aircraft. (And then, everything gets examined).
The cross fertilisation between your medical history and the AME's assessment probably doesn't actually take place in real life. The cross over of information isn't that sophisticated. (Yet).
Having said all that, you've come up clean, which probably says more about your airmanship than anything else. It sounds like it was more an oversight, (did you fully understand the question) than any attempt to deciet, (and it's probably a good idea to stress this point to the CAA).
Having told you how the system works, it's probably a good idea to remind anyone seeking an aviation medical....
Telling lies to your AME is like sleeping with your wife's sister, it seems like a good idea at the time, but it's bound to catch you out in the end
(So I'm told.)