Whats wrong with the prices invalid entries and WorkingHard? They are typical and would have been quoted straight from their terms and conditions pages. If you want to use a major airport then expect major airport prices, so if your pal had landed at Heathrow do you think you'd be allowed to filter a PA28 in the sequence? and if yes how much do you think they would charge?.
If you bothered to look at LLA's web site it clearly states the minimum landing fee for ANY type is £31.05, and the Navigation Service charge (provided by NATS) is £100.93. So £31:05p for a landing fee at a major airport in the south east is not unreasonable I suggest. And if WorkingHard wants to pay a pro-rata rate for easyJet/Ryanair he better start flying his plane through Luton hundreds of times a day, oh and bring about 150 friends on each flight, because that way he'll be able to negotiate a discount on his handling fee!