If you're looking at Oxford for the groundschool I would suggest you have a look at PGT based at Kemble:
www.pilotgroundtraining.com Pretty much all ex-Oxford instructors but you have the benefit of it being a much more personal service.
I did my flying training at Flightpass (Exeter) and can recommend them extremely highly:
www.flightpass.co.uk Similar concept to PGT- excellent instruction, great environment and very personal. I really don't think you will find better.
I would do your CPL SEP unless you have some cash burning a hole in your pocket as it really doesn't make any difference.
I guess most people will tend to recommend the place they have experience of so make sure you have a really good look at the places you're thinking of going to so that you can be sure they're right for you.
Good luck with it all,
NF