I am fairly certain that our LATCC colleagues are not daft ( that should get me a few direct routeings) and they would not promulgate a clearance without good reason,BPK u/s or not.For those with long memories it is possible to find points in space through radials/bearings and distances from other stations and I'm sure BPK can be defined thus.If the F50 crew need any more help with their navigational endeavours they could try following the railway line north from Potters Bar,notwithstanding their heroic efforts so far (sense of humour alert).Toodle pip.....