People in the midlands were driving to stansted as the choice of destinations was very limited at EMA. The extra options at east midlands is reducing that flow. I do not expect people to drive from the south east.
Ryanair do their fare comparisions in euros. They also load a lot more hidden charges on than easyjet. If you have bags to take the difference is very little and easyjet is a far nicer carrier. The average fare is also not a good comaprision as Ryanair bring the average down by dumping unsellable seats onto the market for very early morning mid-week flights to some minor airstrip. This cons the shareholders that they are growing fast. If you wish to go to rome on a friday at a good time you will often pay more with ryanair than BA or anyone else.