Hopefully this won't be a can of worms...
Most of the events I do and indeed the one I am organising are around the 10 pound mark, for that riders get card, validation, a village hall HQ, a light breakfast, some food at the finish and in some cases even some extra along the way. I think it is brilliant value for money.
However, I have also done other events where I get absolutely nothing other than card + validation and pay 6 pounds. Car park start, cafe' finish with nothing paid for and nothing in between, commercial controls.
Now, Brevet card is 55p, validation and a stamp to send the card back (if needed ) is another pound or so. Let's say that overall, the organiser spends 2 quid per rider (and I am being generous as some riders will submit their own SAE, some riders will DNS or DNF)... why charge 6?
How much of this stays with the organiser and how much goes to AUK? If AUK remember, they have a giant white elephant that needs feeding...
Round these parts all brevets are BRM, they cost about €5-6 (maybe a bit more for longer events), and are what AUK would call X rated. Some starts have tea/coffee at the start, if you are lucky there may be a secret control with drink and chocolate, and maybe soup at the end.
It always struck me as good value, and I know that any money left over goes towards helping the national club keep going, and every so often if there is a massive surplus, we get subsidised club kit.
As for your costs listed, don't forget that if you pay by paypal, then that's another 30p or so on your six quid. Then you have the costs for the org of scouting and planning. I don't see a problem with any excess funds going to cover the costs of the org doing their scouting rides.
Ultimately it's all tiny money, and exceptionally good value. I wouldn't quibble too much.
J