It went through MKC about an hour ago heading, I guess, for home base - a picture is on my twitter (@MKDarlo). The first vehicle seemed to be a non royal train vehicle but instead a DBS company train sleeper vehicle
According to my sister, The Grove stopped at Hitchin to drop off the royal party, then disappeared. Probably did a loop via the NLL. The Queen went round Hitchin, then by car to Stevenage to open a replacement for the maternity ward in which I was born, then headed off for Hatfield. I have pictures, but they won't be developed for a while.