If you have £8000 then I would definitely buy new, unless you really need a large/heavy car for many adults/dogs/pulling= trailers that is.
Go on AT and there's enormous choice of sub-8k new ones.
FIAT 500 POP for 7500 even, but I would pick a Panda 1.2 at 6500 or the Punto 1,2 at 6999. Petrol preferable over a diesel, at 25000miles per year you could easily run into their expensive troubles over 50k, even with FIAT's and REANAULT's excellent engines. I am doing 50mpg in my Punto GP 1.2 average ( no motorways involved) , albeit on MOMENTUM 99 premium petrol always.
Beyond FIAT there are other excellent ones, PEOGEOT 208 1.0 VTI would be my choice: frugal engine ( I ran 55 mpg but in amuch lighte C1 so FIAT's 1.2 not bad at all given 20% more weight) and super reliable. There are 200k miles ones advertised on AT sometimes.
I just do not unnderstand why so many people spend 6-10k on 2nd hand cars when you can get new. If you, I would definitely avoid the uncertainty and hassle with expensive 2nd hand dealer cars.
