I think you have got the parking charges wrong. Surely it is not £10 an hour after 2 hours, but £10 for 24 hours?
I've just checked the fees and charges regarding parking and they have changed...
1st 2 hours free
5.00 GBP / tonne (for aircraft with a MTOWA less than 5 tonnes)
Of course this only applies to the 1st 24 hours. CVT have other monthly and annual parking charges but they are not published.