hi, i just had a fuel system cleaning and an ATF flush cleaning.
the car feel much much better, i can even feel the power has increased. they inject some cleaner into the vacuum and for the next 20min... u can actually see black smoke comes out of ur exhuast....... it smell like hell. the guy said that this is all the carbon inside ur exhaust and ur engine.
i don't know does the UK have this service, take alook at this web site in australia, maybe in UK u guys have some service similar to these.
www.megapower.com.au