I think £1000 would be pushing it for a return trip. Don't forget whoever takes you is going to have to find somewhere to stay for the night as well. Fuel will be a good £600 if not more, plus an hourly fee let say £50 on average for the aircraft maintenance fund and landing and parking fee.
Then there will also be Eurocontrol fee as the flight will be at night which means it is either SVFR or IFR. And then the stupidly hiddeous Landing fee back at the UK for the privelage of landing lights
it cost me £504 to Bristol to Lille return last week, and that is only half the deistance.