Putting discussion about who said what where and when to one side, maybe get in touch with
SWAG. Still a stretch from Cornwall but manageable. They sometimes have people doing repairs at their events. Next one is in early Feb so you might be able to go up to Bristol for the day and get your Amiga brought back to life. At the very least they should have an idea of any local-ish repair specialists.
If you search through EAB you'll find various vendors, scope them out, call them up and get a feel for them. Ask about their current load, possible timescales and whether or not they have experience with your particular Apollo.
Yes RP have a reputation for poor comms and slow turnarounds, but I'm sure if you spoke to Steve he'd tell you if he was already booked solid. The only people I wouldn't trust are AmigaKit, because they've they've been involved in enough shenanigans to put me off for life but YMMV.