Thanks for that Boxbrownie!
I should be able to get the brass rod in B& Q and I might be able to salvage the joints. I don't know the part code for rapid online!
It is not urgent as my local garage did a "repair" a while ago for the MOT, but I don't know how long it wil last.
I had previously joined the 2 parts of the broken rod with a piece of electrial type shrink wrap rubber.
That went through 2 MOT's without being spotted, but on the 3rd year he spotted it and passed it provided I had it fixed properly
Amazingly the headlamps had stayed in alignment all that time while the rubber did the flexing and the top ball joint was seized up!
This is not to be recommended