Seems bizarre to me - help please?

[Lovelybus]

Since owning the car, the mirror adjustment has never worked. As it's not really bothered me too much I've left it until now. Trying to trace it now.

Mirrors don't fold when the switch is put in fold position
Neither left nor right will respond to the adjuster pad.

However, with the memory button depressed, then holding each of the four memory buttons down in turn, seats and (the first time) both mirrors move.

After that, each memory position adjusts everything except the passenger mirror, which now doesn't move. If I move the passenger mirror gently by hand, the next time I press a memory button, it will go back to where it is again and then doesn't respond to subsequent memory choices.

Memory module seems like it's ok, motors in mirrors must be ok, and MikkiJ tells me "it's never the switch"

Any suggestions what to try next?