Do second hand carbon booms come around very often and if so do they tend to be repaired damaged items? or is it just better to bite the bullet and buy new?

They come up every so often, but they tend to be old heavy ones. They tend to be about £100

They are relatively inexpensive to buy new, though for 3190 it may not really make economic sense.

" Heavy" you see thats the key word there's plenty of lard on the helm of 3190 as it is so when the time comes to buy a new boom the ability to save some weight is to good to pass by!
The old one has some disimilar metal corroasion and salt water damage going on.

I'd buy a new one and keep it when you sell the boat.

Superspars are about £325ish, Chipstow ones are better (Slightly lighter and much stiffer), but about £50 more.

I got a chipstow and fitted it out myself.