And now I am able to access from the desktop, but then not from my iPad.
Quite a mystery.
1. Was not able to access from Desktop PC
2. Was able to access from iPhone
3. Not able to access from iPad
4. Then now access available from Desktop
All in the space of 5 minutes! But previously was unable to access the forum for approximately 2 hours - it doesn't seem to be a case of clearing the cache on the Browser John. I have used 3 different browsers from the desktop and 2 different ones from the iPad and still the same result.