There is no topo guide for Trewortha although there are some selected boulder problems in the Cheesewring and SE Cornwall guide. The information for Trewortha is all on UKC as far as I know. It will probably all seem a bit confusing at first but, as you spend more time there, things will become clearer. The ferns are just starting to die back so the north side is still tricky to navigate.
If you need any specific help just email me and I’ll see what I can do.