I have. We have an ebike that was £2200 brand new, and it was effectively a 100% tax deduction. And yes there are some restrictions around it but they are easy to work with. I have no comment about employers setting their own limits, that's just dumb.
Props to you, I also use the scheme but I had to get a bicycle one year, then wait, and get motor next year and install it myself. Because of the limit.
Most people would not even realise that there are little shops besides halfords on the scheme, and attempt DIY.
Basically I think it would be much simpler, and cheaper to administer if we did away with all the employer nonsence and just removed all taxes from bicycles, like VAT.