The scheme and work aren’t being deliberately awkward, they can’t give you that number for legal reasons.
I was on “cyclescheme”. The way that works is that they divide the total sticker price (your £750) by twelve and charge you that every month **BEFORE TAX** which means that there’s less taxable pay, so the amount of repayment is lower than the £750 they divvid up.
Where it gets interesting is after the 12th month. The worst thing you can do here is either give it back (!!!) or pay the ballon final payment which is calculated using HMRC provided valuation and will be insane. The scheme I was on allows a 13th extra month to be paid, and then they leave the bike with you – and at month 36 come back and apply an HMRC provided valuation of a now three year old bike and possibly give you a few pennies back out of the month 13 payment as a result at which point the bikle is finally legally yours – at all points up to this it belongs to the scheme but is in your keeping.
The total cost of my £1000 bike ended up being around £650-700 so there is a worthwhile saving but not as much as there used to be, it’s more complicated than it used to be, and your tax code makes a big difference.
HTH!