A bit further south in Maidenhead I can recommend Cordwallis (VW dealer at Maidenhead). The service manager is on here (dazboi), and they are good. Also good value for money and definitely worth speaking to them before you decide where to go.
As an example, they serviced mine recently and discovered I had the wrong size spigot rings on my newly purchased T4. I dont think many VW dealers would have picked that up, or even cared to mention it.