The photos of the dealership & location in the OP should have set the alarm bells ringing. Just go to a respectable dealer and you should be ok.
I ordered my new GTI with Lancaster VW in Letchworth which used to be called Jardine Motors and Wayside VW before it, they are a chain of dealers that are part of a family run business. I've never had any issues with my Mk5 GTI in the last 6 years and I have full confidence in them with the new car on order.