Mark, depends which scheme you are on.
When I did some research recently, different schemes offered different end clauses. As mentioned there should be the option of your employer taking on the ownership of the bike so you don't have to pay anymore - but you still don't actually own the bike
It would belong to your employer.
Then after whatever the period scheduled by the bike scheme (2/3/4 years or whatever) your employer can then pass the bike onto you as the market value it would then hold wouldn't require a final payment.
There's a table online somewhere that gives the final payment ratios of the different schemes but I can't find it at the moment - sorry.