SLR - Where to do a PPI in or near London??

[Brakke]

Hi guys

Just a quick question: im looking to buy a SLR and need to sort PPI.
So it seems MercedesBenz does the maintenance on these car only.

Ive already contacted MB and they suggested the 3 following locations:
MB Chelsea, Stratford and Templefortune.

Im not sure if I should ask advice from the MB section or Mclaren section as well, so ill just do both:
Does anyone have any experience with any of the above or perhaps knows a better place for a PPI??

Thanks