I am always amazed at how people are happy to go for the cheapest flying costs without considering the costs of actually getting there. Mr Newbie, you might want to consider Inverness for your flight training since it is VERY cheap there ;-)
But really, you do need to not only look at the cost of getting to Stapleford for each flight. If it costs you £10 to get to Stapleford and back on public transport, then that is £500, which is the difference in your training fees. Also take into consideration the fact that you might travel all the way there, only to find our that the clouds have come down and you cannot fly. Another £10 wasted.