OK, more to report.
I thought I'd have one more go at installing these to try to figure out what was going on -even though I had the Raspian, updated to Astroberry working. I have a pile of micro sd cards, so didn't have to overwrite the working one.
I found that both Astroberry and Stellarmate work perfectly when installed on 32gb micro sd cards, but will not connect to wifi when installed on this micro sd card:
https://www.amazon.com.au/gp/product...?ie=UTF8&psc=1
This was one I specifically bought for the Pi as it came up very well in speed tests.
After the successful 32gb installs, I tried the 64gb again. I had the same problems as originally. I have no idea why they don't work on this card, but I'm happy now that it is all working as it should on the 32gb cards.
Thanks to OICURMT for those instructions, have copied them as a reference in case I have issues in the future! May I pm you if I have any other queries?
cheers
Gary