The Flight Plan
Flight plans are submitted 'on line'
Go to www.flightplanningonline.co.uk
You will need to register with NATS (it takes at least a week)
Otherwise your local club/flyingschool should have NATS access.
The Heathrow (parent unit) fax numbers are defunct.
You could try Swanwick on faxno. 01489 612 793