I have to say it wasn't being "used as a target" - why the hell should it be? They didn't need "targets", they shot at co-ordinates miles out into the mud as far as I could see, but by 1992 they didn't seem to be firing at anything at all. The TSR2 front fuselage was sitting on the grass behind the sea defenses and probably behind the position of any guns anyway, so no way a target. Just left there to rot.