Didn't the 727 Greenline start at Luton then went to Watford, Maple Cross, Heathrow and finally Gatwick?
Crawley was the final destination for the 727. IIRC it took around 3 hours to get from LTN to LGW in the pre M25 days! (not far off what it can take at certain times today using the M25 without all the stops!)