Alan,
Just to put you in the picture, if I depart IFR from Biggin for, say Edinburgh, it will cost me about EIGHTY MOTHER F

ING POUNDS.
If I am in the fog for fifteen seconds, that works out at £320 a minute
I strongly object to paying Eurocharges when I get no (or very little) service. For example, if I fly at night, after the entire LARS system shuts down, and never use the radio, I still have to pay NATS, a private company that has provided me with no service whatsoever.
I have no problem at all paying for flight on airways (though why I should and a TB20 shouldn't is beyond me), but the current system of making people like me pay a fortune for the whole journey if there is any hint of IFR at any point on the route is what leads us to take risks to avoid the charges.
The really silly thing is that the best way of not paying charges is to file an otherwise spurious VFR flight plan, thus making NATS do a whole lot of unnecessary work in order that they make no income!
The system is broke, but the chances of anyone fixing it are zilch, so I and the rest of us have to continue to buck it.
One very simple solution would be to release non-AOC aircraft below 5,700Kg from the charges.
Now...TAKE COVER, while TC_LTN explodes