I'd make life easier, by saying a man buys the best English Sle gun he can. I'd also take the collector tag out of the picture - not quite like collecting Lefevers in their different grades and conditions.
...but then, who knows that many rich buyers of top English guns eh?
I rate 'em all as shooters, as they are the best in the world at what they do - and I'd rate them as excellent, good and fair - and that would be that!
A newly barreled Boss, by Boss wouldn't cause me to lose sleep either.