I think its Northamptonshire Steve.
I think I'd probably charge about £10-£11 for that job (Here in Bristol), but bear in mind that its only worth doing if you have other work in the area, and preferably close enough to walk to in less than 2 minutes.
Also, if you have to walk for miles to get to the alleyway leading to the back, and then fiddle around trying to climb over a gate (maybe with that illegal broken glass?!) this all takes extra time, and you should charge accordingly.
Even if it doesnt take extra time, I sometimes charge extra if a job's a pain in the neck to do!
Silly