Simon
I would imagine there are many here who are better placed to offer you guidance on whether to go for a JAR PPL or NPPL, however fundamentally I think it will come down to what you want to do with the licence once you have completed the course and your medical situation.
I strongly suspect that there will be little difference in the total number of hours that you clock up whilst learning either one way or the other, in reality few complete the PPL in the minimum specified number of hours and they generally are completing the course on a full time basis so benefit from the continuity of training that is often lacking.
I would think it better to view the course as flying in itself, rather than get hung up about the number of hours that it takes you to complete, things will probably continue in the same vein for you once you have finished the course.
If you harbour any aspirations to fly outside of the UK, perhaps to the French coast for lunch or somewhere more exotic, or if you think there is a possibility that you would want to take your flying further and undergo professional training then I think the PPL is for you. Then again if you think there may be possible problems with your medical renewals and only really want to potter around the UK or your local area then the NPPL is probably for you.
Sorry I cant really write knowledgeably about flying schools near Bexleyheath , I’ve no doubt there will be people here who can help you out.
Good luck with the flying either way – be warned however this game is addictive and your wallet might start hurting real soon!
Happy Christmas