I'm sure they would love to meet you and do some business with you - not sure why no response as of yet. I'll echo other persons sentiments by saying I had a very positive experience there, went just to poke around a bit and came out with some of Mr. Felton's DVD's. I look forward to going back.
Although my experience shipping overseas is limited (and somewhat dated) take my comments as opinion only until validated as fact. I think you would have to pay sales tax if you walk out of the store with the bass - then you would have to declare it upon return to the UK. If you had them ship it there direct you will most likely avoid the sales tax but have to pay for shipping and any duties when you went to pick it up from wherever they shipped it to.
It would have to travel via US Postal Service - I don't have a clue what the cost would be. I do know that insurance liability is very limited. The amount you spend on a bass will play a large part in all of this math.
Anyway, have a safe trip and enjoy Bass Central!
Gaddis Tippett Custom 5, Circle K Strings, Micro rig: Ibanez IBZ10A acoustic guitar combo w/chorus!
SWR Club #185, GK Club #971, FL Bassist Club #254, Mediocre Bassist Club #933