After a long delay I have received a reply from Humax.
1.With batteries out Press & Hold the Power Button on top left corner for 2 minute. This completes a static discharge.
2.Batteries back in Press & Hold the OK & 0 buttons for 10 seconds.
You will see a message on screen. Immediately press number 2.
This put remote into Mode 2.
If you don't see a message on screen repeat until you do.
Will see if this solves my intermittent remote, although previously it has worked fine until it decides to go intermittent again.