I tried the code anyway and it worked after I realised that the bbpress forum pages were linking to the primary theme (iFeaturepro5) rather than the child version I have created. I really don’t understand that at all because the Child theme was the one activated at the time. The main thing is the side bar has gone.
Anyway, thanks for the help. A final touch would be to be able to reduce the size across the screen a little. Is it possible to change from full width to a percentage; say 80%?