I fear there are an awful lot of urban myths flying around (unlike Buccaneers which remain Earth-bound unless you're in SA!).
I suspect the "flying through the hangar" story developed from the many low level flights performed over HOSM where (as has been said above) an awful lot of astonishingly low photos were taken. I believe some of the flying over the airfield was quite spirited at times, and I'm sure that a few development aircraft slipped between the hangars. As for flying through, I think that can be safely regarded as a myth. The Buccaneer's a surprisingly bulky aircraft and British hangars are (proportionally) quite small. The odds on getting a Buccaneer safely through a hangar must be about zero and I think it safe to assume that nobody would be crazy enough to even try it.