A and C
Per Pooleys Flight Guide 2002:-
"Elstree Landing Fee: Up to 1360kg £17.02 Plus VAT, 50% reduction for cash payments"
That comes to exactly £10.00 INC VAT, for cash payments.
LPlate
I would suggest that you look at all the schools in your area. You can also take trial lessons at several, if you wish, before you make up your mind. These can be logged towards your licence.
In aviation ,you tend to get what you pay for.
Cabair is certainly not the cheapest, but it does have high standards, high pass rates, newish aircraft & sufficient aircraft so that you do not have to wait.