We were also good little boys and fitted a TRS80 in our C-150 when the old mode A only one went unreliable. It seems we are affected by the AD so we're going to have to placard the aircraft and insert a note in the POH basically saying unless they say it's OK do not fly into airspace that requires a transponder and is mode S equipped because your shiny new mode S transponder is a piece of junk.
Anyone know what airspace in the UK apart from Heathrow Zone is currently affected?