I live 75 minutes out from LHR, 2 hours in bad traffic. I would not like shorthaul any further, and even that is too far for quality of life. Local accommodation will be essential- it is not fair on your colleagues to be knackered when you turn up for work, and exhausted during the day. It's not sustainable unless you stay much of the month nearer the airport, and there is talk the CAA is examining the fatigue aspects of living so far away. Most companies now require you to have an address nearer.