alternatives
If you have a flight to catch from LHR or GTW early in the morning then you must stay near the airport overnight OR hire a car and leave about 4 AM OR if the sleeper train still runs catch that(about 6 hours!!).So its going to cost you money whichever method you use.I used to hire a car .Of course at one time you could fly into LHR and then BA ran Brymon long enough until they could grab the slots then they got rid of Brymon/BA to South West ,clever ploy!I no longer live in Plymouth but would still like the choice of flying there than travel Great Western on a crowded train where you must stand for 3 hours!!!