The above accountant type stuff is bang on.
I've had a couple on interesting questions raised from a VAT inspection about keeping the bike at home. For you not to pay a benefit in kind charge the vehilce should eb used for commuting or be kept anywhere excpet to the work address, with the exception of doing deliveries/site visits etc out of hours or on the way to/from home. I persuaded them that as the bike can only be insured properly at my home address and that it is only properly secure there ti should not be considered for BIK. They agreed, with a sly smile on their faces, however this was backed up by the fat that I claim less than 2500 business miles per annum on my car thus supporting my claim that the bike is 99% used for business (which it is - even the charity run is counted as business).
As for equipment - all normal running costs (fuel, servicing, spares, accessoroes) are tax deductible and vat reclaimable.
If you look as though you are hiding something they will shaft you, however be open and up front and they will ignore the small stuff (racing can, sticky tyres, dayglo leathers)