These two chapters have appeared this morning on the TSO website as published today and available for dispatch. They are still described as “2018 edition”, as that’s presumably what’s on the cover.
Chapter 7 is much expanded with all the important directional signs from the 2002 TSRGD illustrated (so you can now put that document to bed). It’s also got guidance on the new forms of dedicated lane signs, tourist gateway signs, and advice for bilingual signing in Wales and Scotland.
Chapter 5 is somewhat slimmer than before, as most regulatory markings have been moved to Chapter 3 (expected very soon). As a result, the changes needed for it to work with the 2016 TSRGD are fairly minimal – mainly inserting the new Sx-y-z form of referencing.
I understand that the PDF versions should also be available pretty soon.