A sort of 0800 WXBRIEF
I'd pay 100-150 GBP per year for unlimited use with a freephone number (so you can call from a call box), but what really puts me off are one off 20 quid charges per call. It'd be nice if you could talk to a pre-flight briefer who could remind you of Notams, weather etc., and then go ahead and file your flight plan for you.
EA