In reply to Sam W:
2nd hand can be fine, if you're careful/lucky.
My commuter bike is a second hand bike from a reputable dealer that someone had traded in as the wrong size for them. Been fine for me and meant I got a lot more for my money than I would otherwise have done - can't remember exactly, but something like RRP of £1800, I paid ~£700 and the shop set it up for me.
Bought my wife a barely used Giant road bike on eBay last summer - owner had bought it to do a couple of charity rides with work, but decided she preferred mountain biking. RRP £830, we got it for £130. My hybrid was mint and less than half RRP on eBay, too.
Equally, I nearly bought a 2nd hand road bike from a colleague of a friend of mine. Rode well, seemed a good size, but final inspection before parting with cash revealed the head tube had cracked where it joined the down tube, so walked away from that one. I don't think he was trying to pull a fast one. Point is, if you go 2nd hand, have a damn good look at it and make sure you turn it upside down.
My best bike was a project built up from parts to my own spec - all bits from sales and got a very nice bike for a lot less than the equivalent "off the peg", so that might be worth a go if you have the time/skills.
If I was you, with that budget, I would get properly measured by a good fitter (~£100) if you don't already know your size, and then start out looking at sale bikes in your local bike shops and get haggling. Maybe look to spend around £1500 on the bike and that'll leave you a bit spare for pedals, bottle cages and a wheel upgrade - stock wheels can often be rubbish at that price point, as they'll expect you to want to upgrade.
I'd personally be very wary of spending your sort of money 2nd hand and especially on eBay - a couple of hundred quid isn't the end of the world, but that's a lot to lose if things go wrong and you've no comeback.
edit - just noticed your comment about working in a bike workshop, so looks like you do have the skills to build from parts. You'll definitely get something unique that way
Post edited at 10:15