Have you heard of the government's Cycle2Work scheme? Possibly not, because it hasn't been well publicised. This is an initiative where it is possible to buy a bike and accessories tax free if the bike is used to commute to work.
Details can be found at:
http://www.bikeforall.net/content/cycle_to_work_scheme.php.
This is a salary sacrifice scheme which would be administered at work, so you need to get your employer on-side. A monthly deduction is made from your salary over an agreed period (usually 1 to 2 years, I think). Technically, the employer owns the bike during this period and you are leasing it, but once it's paid off you can buy the bike outright for a nominal amount. Very large savings are possible through the scheme.
The scheme is run through a facilitator organisation, and there are a number of facilitators - details can be found on the bikeforall link, above. Quite a lot of bike shops in the area are part of the Cycle scheme set-up ( http://www.cyclescheme.co.uk/). A potential downside is that you are supposed to use the bike mostly for commuting.
Only a desk-sucking, non-cycling bureaucrat could have come up with a bit of nonsense like that!
I haven't yet bought a bike through the scheme, but I am currently getting my employer to start the process. I'll let you know how I get on.