Thanks for the replies so far, folks. I have tried all the options, including 'enhanced interface' - no change. It was all working for me but can't say when it went pearshaped, except last few days.
I love pprune, but if it's a case of having to use IE instead of Firefox......
Footnote: I see in posting options that HTML is OFF - would this have owt to do with it? Raised this with admin to no avail.