Sole trader - bike as a tax write-off?!?

Hello,

I'm a sole trader and cycle to my office on a beater that is slowly giving up the ghost and needs replacing. I also fancy a nice shiny new carbon steed. Can I combine these two needs and get some sort of tax benefit? I would happily ride the new carbon to work every day as I can bring it into my office.

I read this from a bike shop website after figuring out I cannot setup the cycle to work scheme for my company:

You can still make savings however, if you intend to use a bicycle for work-related journeys. You would purchase the bike from Edinburgh Bicycle in the normal way (with a company credit card, cash or by making a BACS payment) then claim back capital allowances and write the purchase off against tax. If you are VAT registered you may also be able to reclaim the VAT. To do either of these you will require an invoice from Edinburgh Bicycle addressed to your company and we can supply this to you if you complete the Small Employer application form.

And also this page:

http://www.hmrc.gov.uk/capital-allowances/plant.htm

But it doesn't really give me an answer suitable for my tiny dunce mind. If I buy a new bike and ride it to work, what can I claim back from it on my tax return? Can any tax/business heads break this down for me please? I'm not VAT registered, FYI.

Cheers