thank you for getting back to me - this is what I have tried so far:-
Changed the battery in the remote (all other remote functions work - e.g. I can switch on, off, vary the background lighting and switch the first heating setting on off) - the only thing that doesn't work is if I press the button for the second heat setting.
I also checked the internal fuse (although I figured nothing would work if that was gone).
I also tried all ten different frequency settings on the remote (only the initial setting works - all of the others do nothing).
I am guessing that either the remote has a fault or that in the heater the receptor has a fault, or the fan/element that is meant to come on extra has a fault (the fan used to get faster/noisier when you pressed that button).
What I can't find anywhere is a circuit diagram or any information about what is inside the heater - or where to get spares from. I could easily try a new remote, a new control board etc. but where do you get them from. The DeLonghi site doesn't even seem to list these heaters.
Pretty sure this is radio frequency remote, not an IR. There is no IR window on the remote and if you cover it up or stand around the corner, it still operates (IR is line of site and will not work if covered or around the corner).
The red LED on the remote operates when the button is pressed - same as it does when other buttons are pressed.
That is the website I found - but I cannot find any mention of this fire on there - I will try to give them a ring and see what they say!!!