LTNman -
You were right about the M1 - now running with 4 lanes open both ways between J10 and the M25 - and a very short journey even at busy times. I hope the airport will make every effort to promote good communications, now they are finally in place. Luton will be easier to reach than LGW from Central London, with clear motorway to M25 and North Circular, good train services from both north and especially south.