AIR
Daily Ryanair flights to Carcassonne and Perpignan from Stansted.
B.A. fly into Toulouse from Gatwick. Some good deals are available but be prepared for some antisocial flight times to take advantage of cheap rates.
Easyjet fly to Toulouse or Barcelona but not on a daily basis.
Look for regional (Birmingham, Cardiff etc.) flights to Toulouse, Carcassonne, Perpignan as these are changing and being added to all the time.

ROAD/FERRY
The distances from Dunkirk and Calais are almost identical and Norfolk Line via Dover/Dunkirk sometimes have some very good rates available.
Otherwise P & O/ Stena and Seafrance are the standard ferries although it is worth looking at Hoverspeed as well. It is much quicker and sometimes is no more expensive..
The mileages and times that have quoted are all via the peage (toll) motorways.They are generally 3 hours quicker than the route national. Approximate peage costs are £40 each way.
The Ferry service from Southampton/Caen might suit you as it is an overnight ferry, giving you a very early start on the road at Caen.
Eurotunnel is by far the quickest route across the Channel.

TRAIN
The nearest TGV depot is at Toulouse.

Full directions for finding the house/collecting keys are sent out with the booking confirmation.