Thanks all for the insight.
A massively grey area in terms of enforcing the law then!
I've read through both the RCD and RCR wording and some supporting documents around compliance and have a clear sense of the fundamentals.
I guess what I'm asking here is for the unanswerable...five plus years down the line are we going to be treating compliance with a firmer attitude?
Ultimately this is probably worth the risk for me, as this is a second boat that I envisage keeping for quite some time. The hull is in excellent condition as is the engine.
A PCC is being heavily recommended by the surveyor, as a method of protecting myself in the future from sudden. He's got no affiliation with anyone offering to do such work, so I trust his view as a balanced one.
Seems we're approaching a crossroads with how we treat RCD/RCR, so It'll be interesting to see how it all pans out. Especially, as pointed out elsewhere–with the ever growing fleet of sail away widebeams we have here in London and the South East!