A Bass Bash would be a great idea!
Sadly I have to echo the sentiments of those above - there are no decent shops on this island to try out bass gear, unless of course you're after an Aria or a Westfield! Marcus Music in Belfast is closed now too, which used to be the best in the city for basses. I think Matchetts have a few £500+ basses in, but even at that, you aren't spoiled for choice.