Okay - so to recap - we found Baschurch. Easy.
Then on the internet is "The Royal Oak" motel, built by Jenner - who at one time claim it was the first location for the crossroads motel.
Now...
On this forum I have done many screen captures that link The Longshoot in Nuneaton to the exteriot chalet designs (as seen through the 1970's staffroom window). But its built of brick
I have also visited Baschurch.... the college is built of brick...
There are a couple of things that point me in the direction that perhaps - even if the producers didn't use The Royal Oak, then some images may have been used to form the basis of the motel...
So - the chalets in episode 126 / 500 etc have stone walls - as does the Royal Oak. If you pause the screen outside the reception you can see what looks like a two story building - like the Royal Oak...

%20Projects/Royal%20Oak.jpg)

Source:
http://www.woodhall.co.uk/(E)%204.3%20Royal%20Oak.html