Sorry, but I have to agree with bose-x on this one.
It is an unfortunate fact of life that the larger airports with full ATC and handling facilities have much higher overheads than most of the small, (mainly GA), ones.
£45.78 plus overnight fees of £10 are certainly not the worse I've come across for one of the larger airports. In fact, on my last visit to Hawarden, (full ATC, but much smaller), I was charged £20 landing fee, and not allowed to even go to the clubhouse! - all I was allowed to do was walk upstairs to the top of the tower, pay the fee, then go (and they were damm miserable on that day too).
On another note, I did most of my training at Bournemouth, and always found ATC to be polite, courteous, and above all helpful.
So, much as I don't like it either, (cost, that is) what bose-x has said is, I think, a reasonable take on how things are.
ariel (and no, I'm not a washing powder)!