Whilst REVO have an excellent name i'd be a bit worried about the people they are using to install some of their maps - from the description the place used by FroGTi sounds like a right shower, where i wouldn't take my old MkIII never mind a new GTi.
My Revo dealer was APD in Dorset, they are a small independent but really know their stuff and are extremely helpful. I must admit though, as a business owner myself, if a customer was coming from France I would be on time and have the (proper) coffee already brewing.
As for revo selling direct, they do at shows and I think you can go to them direct. I guess not everyone can or want to travel to their HQ? My experience of Revo as a company has been very impressive, really professional guys and ultimately the end results are impressive for the price.