well I set up a shop a few years ago and its been growing ever since, and its hard, but rewarding, we held our first race at the weekend and its a lot of fun at times.
just beware that the distributors and suppliers are totally shit in the UK.
I am looking to get products elsewhere as they either sell all their stock to the big internet companies and leave you with back orders that can take months to fulfill making you look like a tit and the customer then more detemined to stick to online ordering or they dont carry sufficient spares to fulfil warranty work, but the job is cool and its not going to make you a millionaire.
but get a good local scene going, sort local rides and do a good job of fixing bikes, and dont worry too much about the internet forums as the guys on here are the minority not the rule.
your average biker hasnt heard of singletrackworld, bikemagic, bikeradar etc.