1 - I believe all the schemes are relatively the same however I can only offer advice on using the cyclescheme. Looking at
Evans it appears to be the same as the cyclescheme however you're obviously limited to only using Evans.
2 - Again i'm not sure how it can be done by yourself, unless you possibly have a company? As far as I'm aware the following applies in the example:
Bike costs £800, your work will pay the £800 to the cyclescheme.
You then pay your work back that £800 monthly from your pay (salary sacrifice) before tax/NI - this is where you save money. Your company in theory also saves money as they won't be paying the company contribution NI on the salary you're left with.
3 - This is where it's a grey area, your work own the bike however you have to provide insurance for it. In theory you should have advised your work that the bike you had was nicked, which in return your insurance company should have paid the money to your work. This would have ended your cyclescheme contract and you'd have to start another 1. I'm currently riding my 2nd bike after the 1st was written off, I've not told my work
The end of term valuation is really down to your company, they're not able to simply write the bike off and give it to you, there has to be some sort of transaction which is why my work charge me £25 and invoice me for it.
4 - You're required to maintain the bike, if you're required to get the bike valued then you simply explain the fact that you've upgraded it. However I know quite a few people that have taken part in the scheme and never actually had to have the bike valued at the end.