@Dave Bevan wrote:
my setup is now very similar except I don’t have a split control and it exits to a jaming cleat under the boom instead.
That is exactly how the builder delivers new boats and what I tried to describe. Again you have proven a sketch is much better then text to explain these details.
And Dave Mac, before you go on a shopping spree, I would suggest to take the block from inside the boom and clean it with fresh water and maybe some soap. Then lubricate it with Teflon (PTFE) spray. There is a good chance it will run smooth again for another few years.
If the rope work is undamaged, put it in a pillow cover or in a (cotton) sail bag and wash in your laundry machine just like your clothes. Washing will take all the salt out and most of the dirt. In my experience a rope only needs replacement if it is damaged (i.e. chaffed). And even if it is damaged, cutting a few inches of the end may give it a new life again.
BTW it may be an idea to put all other all ropes in the same pillow cover too. I wash my ropes at the end of every sailing season, just before everything goes into winter storage.