The journey to the campsite near Sarlat is about 550 miles according to the route done on Tyre by Google maps. With Reggie onboard we decided to break the journey about halfway and so the hunt began.
Once I had a route in mind that avoids Paris and the terrible Périphique and the slightly less terrible outer A86 ring.
In the end "halfway" looked to be Orléans or that area. On booking.com I did a search and selected the Campanile at la Source just to the south of the city. Given the time of the outward Shuttle I expect we'll be there in good time to give Reggie a decent walk on the nearby fields.
I emailed to find out how much it will cost for him and it's an extra €5 a night. Amazingly, at this particular hotel he is allowed in the restaurant. Although the idea of dogs in restaurants doesn't appeal to everyone, a well behaved dog is hardly noticeable on the floor and is no dirtier than the shoes that people come in.
In the end I have booked in there in both directions.