[93240se]

You are lucky Derek, mine snapped off at the end of the mast bit, leaving it flush. However there is a quick "fix" if you are reasonably handy. I drilled out the base part with a 3.5 mm drill and used a 4mm tap, same with the actual aerial but it is a bit tricky, took me about an hour in total. I cut the head off a 4mm screw to a suitable length and inserted in both parts.Looking at your photo I would be inclined to do the same thing but measure the thread part that has snapped off and repair as above using the same thread as the part that screws into the mast. This is the second time I've used this fix, whilst waiting to source a replacement ! Make sure you have the rubber seal at the bottom to insulate the mast from the body, or you'll get no signal. I lost mine but used a rubber tap washer between mast and base.
Good luck however you choose to do the job.
Regards, Richard.