Hi Nathan, 
  
I have today booked my car in next thursday for a P3 service.  I phoned Bristol(wessex) and there price was £317 but they do not replace coolant or brake fluid, only top-up. 
I then phone Howards in W-S-M and they charge £259 and that includes all coolants and brake fluid replaced. Also i get a car for the day so that seems very good to me. 
I will let you know how i get on.