I suggest you check carefully what is included in that £6900.
Typically deals like that cover only the minimum 45 hours training and most pilots need more.
Is the cost of the examiner and the aircraft for the skills test included - likely to be up to a couple of hours flying plus the examiner's fee.
Does it include the ground exams, nine of them at £25 each if I remember correctly. What about the radio license test? Is that included?
Landing fees away from home base? Included, or extra?
But don't let this stop you - just don't think it can be done on the cheap. You'll need as many hours as it takes - and you'll probably enjoy every one of them!
Maybe try to contact a local pilot or student who's done the training at that school. Check it out.
Good luck to you!