The following method will reset the datum if the lift ever loses power, it is a guide only to get the lift operational again but if not qualified you must have this checked by a competent stairlift engineer.
“Drop the front panel, flick switch on the board to program. You will then be able to drive the lift to the top charge point, this will reset the datum
Drive the lift off the charge point, flick the program switch off and now the lift will remember its old program
This will get the lift running but I recommend you get an engineer in to check final limits etc are programmed”