No that's not how it works. VAT is taken out before the balance is taken from your wages. Saving 15%.
Then 85% of the cost of the bike comes out of your wages, in the case of a higher rate earner 40% tax savings on that is another 34%.
Higher rate earners earn above the NI threshold so there is no real saving there. (A tenner according to the
Evans calculator, .1%)
Total 49%. Less fees and termination payment. 40%
A basic rate tax payer gets 22% of the 85% back which is about 19%.
NI 12.5% (your number I've never been sure about that) of 85% is 10% saved. So there's a total of 44% savings, less fees bringing it down into the low 30s. Not as low as I orginally said because I'd forgotten the base rate is now 22%.
The Evans calculator shows a different figure because it still uses 17.5 as the VAT rate and 20 as the basic tax rate, but it is still ball park.