Absolutely outrageous, and I am very disappointed by the pathetic response of AOPA, who should be leading from the front. Most UK aierports are managed by people who have no sympathy or understanding of GA, and they aren't interested in GA because they just want to attract B737s.
A few months ago I landed in Bristol (Lulsgate) in a Seneca - on my own. I parked nxt to the Aero Club and got charged the thick end of £160 for a short term visit. Meanwhile Ryan Air were landing for £1 a passenger.
Now what expense did I cause Bristol? They had ATCOs sitting there, they had a runway that did not need relaying or resurfacing for me, they didn't even bother with dealing with me in any other way except for giving me a landing clearance.
Frankly the whole thing was outrageous, and I protested to AOPA about it, in the hope they might at last make an effort. As far as I know nothing whatsover has been done. (I accept that even if they had done something, persuading current UK airport management would have been a hard task.)
It really is a pity this issue isn't being tackled properly.