An interesting equation to do, is to use the Bank of England’s inflation calculator and see what the AP back then would cost now (albeit the BoE calculator currently only goes upto 2019):
https://www.bankofengland.co.uk/monetary-policy/inflation/inflation-calculator
Thus, for example a £5k AP back in 2009, is a £6757.41 AP in 2019.
No doubt it has risen a bit further upto today.
It does make the VW vehicles available on the scheme nowadays seem a somewhat bargain, compared to 2009/2010.