I always found Noble Marine to be very good for my BREx, including several quite expensive racing claims (not all my fault!) On racing dinghies, none on BREx. Recommended.
NM Not at all competitive on the BC 26 tho. Perhaps too much of a yot, rather than a dinghy?
BC26, best deal was Haven Knox Johnson. As long as I limit myself to racing only in smaller local regattas etc. Otherwise started to get expensive and fussy re surveys etc.
No ARC rally, not even Cowes week for me
so check cover for Sail Caledonia and the like (with a trailed boat, of course) if you plan on any significant events.
Strangely enough, "Cruising area" is far wider than that with which I feel safe/comfortable on a 26ft boat. I won't be utilising my Baltic Sea cover!
Not sure where a BR20, or indeed BC 23 might fit? Read the small print carefully.
I've towed Bristol to Derby many times (Hartleys dinghy builders in Derby), sometimes via Blackpool return. The M5_M6 is no fun, and GW gives good advice about the inevitable lorries, towing mirrors, tools etc.
Presumably you have a spare wheel?
With a more powerful diesel 4×4 (and a lighter boat!) I'd set my adaptive cruise control at minimum offset distance and 59.99999 mph, like most trucks seem to, and go with the flow...