I think your total cost will very much depend on timescale. If you save your money first or take a loan and aim to get the PPL done in 3 to 6 weeks, it would likely cost you alot less than having a lesson a week for two years.
I would say £10k up to maybe as much as £15k for busy small commercial airports like Biggin or Southend depending on lesson frequency, and upto £10k at busy airfields like Stappleford. Probably a few grand less at small, quiet airfields.
You need to think about what you will do next because a cheap PPL isn't necessarily best but why spend money if you don't need to.
Most PPL packages will include the theory exams and also a number of circuits and landings (not as many as you will need). Also membership for a year.
Things to think about that will cost money-
Transport to the airfield.
Circuit/ landing fees (home airfield mostly, but also visited airfields).
Fuel surcharges.
Time spent waiting at the hold for traffic.
Class 1/2 medical plus transport to Gatwick/ Ame.
Books, whizz wheel, ruler/ plotter/ protractor, chart pens, flight board.
map/s.
Headset. (good investment)
Exam resits (not free).
Membership if over 1 year or 6 months or 3 months?
Flight test aircraft hire. (quite expensive)
Examiner fee. (very expensive)
Licence application fee. (ridiculuosly expensive)
Ultimately even simple mistakes can lead to you paying out alot more. For example redoing the qualifying cross country beacuse you got lost or had a rough landingb or made a dodgy join, might easily add £500. A partial/ failed flight test could be even more costly.