Thanks for the replies and I have now tried / considered them all ....
Last night as I returned to my car (which was unlocked) I pressed the remote to open the boot, nothing happened so I used the key and that set the alarm Off, I used the remote to reset and then drove away.
At my destination when I tried to lock car with remote I could hear the locks 'click' but the indicators did not flash and the door did not actually lock (I tried several times). I used the key to lock doors and left the car (alarm not going off).
On return to car remote would not open doors and I used key and then drove home.
When home I tried remote to lock doors and it did as it should and indicators flashed and No alarm all night.
I went out to car today and boot opens fine with remote and ALL seems good, (doors, boot and no alarm)
Only thing I can think is key has reset after using manually to lock/open doors ??????
I will continue to monitor .............. (remote has new battery fitted couple of weeks ago)
thanks for help/suggestions.