Accountants ARE helpful.

AFAIK you can't claim the cost of the bike for getting to work if you have a usual place of work like an office. if however you work at different locations and have an office at home then you can claim for the use of the bike for all the journeys you make.
Or if the bike was left at the office location and you used it for work once you had traveled to the office you could claim 100% of the cost of the bike (over 4 years as a capital allowance)

But if your self-employed/freelance, with no fixed office space, then you can? Without a maximum time limit?