Hi jens0n,
I'm am Essex man too, but at the opposite end of the County. I recently bit the bullet and went round to the Mizuno Performance Centre at Silvermere Golf (almost next door to Burhill) for a re-fit (I was left a bit confused and non-plussed by a fitting at a local Mizuno fitter). It's a long drive for you, but the facility is absolutely top-notch and the fitter I went to (Jamie Northcote) was superb.
They're a Performance Centre/National Fitting Centre for just about every brand on the market and you can be assured that they will have every shaft there is (unlike some smaller Mizuno fitters). They use proper balls (Z-Stars) and even have a club building facility on site if you need some other strange tweak! Unlike some places he didn't just go with the DNA recommendations, he looked carefully at the swing, ball contact and flight data and recommended a different shaft that was absolutely a revelation.
A worthwhile testament was that I was also after a driver, but he couldn't find a combination that worked as well as my own and so just said to stick with what I've got and not waste my money - absolutely no hard-sell.
Highly recommended - they also refunded the entire 2.5 hour fitting session fee against the purchase of the clubs I ordered (MP18, Fli-Hi 2 iron and a TM M3 3-wood). Clubs arrived at my house yesterday - just 6 working days after the fit. Happy man.