I agree about the site, I won't use it either due to all of the cookie nonsense but it was the only place that I could find anything about the 710. I will take a look at the GR 650a and see if it appears to be similar. FWIW, I'm surprised at how difficult it is to find any documentation on some of the old Fluke stuff. Radiomuseum was the only place that I found any mention of the 710.
OTOH I guess that I could list to 710 on Flea-Bay with the title RARE! :-)