Thank you that worked fine, sometimes you just have to take the simple route!
The bad news …waking up at half past 6, on my day off, and seeing this message; therefore instantly activating my brain. The good news …the problem is fixed before breakfast. YOU ARE A LEGEND! You are a legend I had tried renaming my theme folder and even tried naming the plugin folder (which doesn’t work as too many things call the plugins) so I was at a loose-end and about to rebuild. However, I was confident that my custom functions file was clean, despite calls for the groups (as they were all contained in “if”s …So I began naming all of the plugins that controlled groups in buddypress the two in question were “Buddypress group control” & “buddypress groups extra” I now have groups re-enabled and also know how to safely disable it. THANK YOU!