Matt,
Don't know where you looked but your not exactly correct.
Civil Aviation Authority Home Page and use the search field to find LASORs
Section C2 details the requirements for a PPL(H).
Minimum course hours (without any credits for military flying, or holding a PPL(A)) are 45 Hrs.
The 25 hours of dual must include 5 hrs of simulated instrument flying.
The exact wording is 10 hours of supervised solo flight time - and this has to include 5 hrs of solo cross country flying and one cross country flight of atleast 100nm to involve full stop landings at two different airfields in addition to the airfield of departure.
The figures quoted are just the minimum. So if per chance you completed all the dual syllabus in 25 hours then you could do more solo flying etc etc.
That said average course duration is probably closer to 60-65 hours for many students, so I would not budget on just the minimum hours
The price you quote for dual more than likely does not include VAT, and in addition may not include landing or circuit fees. The solo rate you mention probably also needs VAT added and is more than likely a Self Fly Hire rate (ie what you'd pay once you held a licence and were flying solo). See the bit above - your solo flying time during your ppl course is 'Supervised' solo - ie an instructor is supervising what you do from the ground and will therefore be billed at a dual rate by the training school.
Also budget for a medical, course books and equipment, a ppl skills test fee and the flying time for the test (roughly 1.5- 2 hours), and the fee the CAA will charge you for the issue of your licence.
Rgds
FW