Hi Pete,
As a Brit who relocated to the US in early 2001, I can give you my 5 cents / pence
. PJ is right - in my early years, you were lucky to see a lefty anywhere. I found a basic Aria pro 2 and was happy to have something the right way around. Generally, it's the same major brands for new gear, but the price is almost the same in pounds as you'd pay in dollars, so you will be hurting. Here's an example:
http://www.guitarguitar.co.uk/bass_guit ... ry=GUBA_lhI'd grab a copy of Bass Guitar Magazine from the Airport/ train station when you land. It will keep you entertained and generally has a lot of UK stuff reviewed in it, in addition to the stuff you see everywhere else. (you can get the mag digitally on the iphone/ipad if you prefer).
This guy has some crazy stuff:
http://www.andybaxterbass.com/Mostly righty however
These guys have a few tasty lefties:
http://www.bassdirect.co.uk/bass_guitar ... itars.htmlThey are in Warwick, however, so it's a bit of a train ride from York, but very doable (its about 120 miles, so a day trip).
For used gear in the UK, I've had good luck finding stuff on:
http://www.gumtree.com/search?q=left+ha ... max_price=although I have not purchased anything BTW.
Happy hunting!
Cheers,
Dave