Motorlift 5000 with bad memory

[71MGB]

Thanks for that, I don't think it is a range problem as I can see the little green light on the back of the unit up to about 10 M away through a door in the back of the garage and it still flashes whenever a remote is pressed but the door opener only responds if I constantly pair it to a remote.
Just had a look on ebay and there are receivers and remotes from china for a fiver that say are for that sort of application.