> TBH, I'd take that as a hint of "thanks but no thanks" and wouldn't
> waste beef on them.

Not true. I've made well-done roast beef (as requested) for them
before and they loved it. Some people just don't like rare beef... I
don't understand this either. In fact, I bet if you did a survey
across England, most people would ask for their beef well-done or
medium, not rare (and I find most restaurants in England think "rare"
means "medium").

Fact is, we offered other choices, but they still wanted well-done
beef. Yes, perhaps it is a waste of a beef joint, but this is why I
thought slow roasting it might make a well-done (read "tough") piece
of beef a bit more tender. I even considered doing a pot roast, but I
haven't done one before and didn't want to chance it on Xmas day.

We live 5 mins away, so I'm planning to take the joint out of the oven
just as we leave. That should give it something like the right amount
of time - or perhaps a bit extra - to relax before carving.

Smoked Scottish salmon sounds like a very nice idea, though. If I
lived local to a decent producer I would do likewise.