Can't see how it wouldn't. Khan may not be the draw people think he is in the UK( I'd have no idea), but people would either get behind him or come out for the event anyways if this were to happen surely. I'd imagine Mayweather could draw a good crowd in the UK fighting just about anyone good. Not to say he's a big deal to anyone, but there is definitely more of a devoted fan base for boxing over there.
I believe that all of Floyds fights with the showtime contract had to be at the MGM grand though, and he'd still have 2 left, so fat chance of this.