I think the above have mentioned most of the possibilities. So it's....
Pooleys to check for
PPR.
Go to the big
C to pay your
Cash.
If you need fuel, it is easier to taxi to the pumps after landing, (with directions from the tower.) than before take-off.
Then some airfields require you to Book-Out, so ask for an internal phone and dial the internal number of the Tower.
.