I knocked the unstable top from a factory chimney in Devon just by pushing it with the main wheel of a Wessex 5. Worked brilliantly and we got a nice bottle from the factory owner. I've got a picture somewhere and I'll see if I can find it. (I suspect that the undercarriage of the Wessex was a lot stronger than those stuck on nowadays judging by the thumping they took doing engine off landings without using the collective................ but that's another thread I suspect!)
PS FAA? Who they? Keeps coming up and they seem to lack a sense of humour.............(I thought it stood for Fleet Air Arm - and they certainly don't lack a sense of humour)