Hi Welshboy...
The problem with your question is that sometimes it seems as if EVERYONE commutes from Manchester. There are absolutely hundreds of crew who commute down each week and it has gotten to the point where a huge amount of crew (even crew with very high seniority after doing years and years with the company) just dont bother to fly and pay the high car park fees but instead drive down to LHR for every trip.
If I were you coming in as a newby it may be better for you to drive the trip instead of fly!