Thinking the dog, on the adapted stair lift, might be more at risk of accidentally stepping off the rear, than her trapping her feet on the leading edge, against the stair - as well as the possibility of her needing to use the lift, to go down - I transferred the vertical board, to the rear....
She was happier, climbing on the lift to go up, in fact now she voluntarily climbs on, and gets impatient, waiting for the button to be pressed to take her up. Happy to ride up, with, or without the front, vertical guard board in place, and stands well clear of trapping her feet at the front. So I transferred it to the rear, which caused absolute her absolute chaos, at first. She found it caused her lots of confusion, she just couldn't quite work out, at first, how she was supposed to fit on the board, to ride up. It took lots of coaxing. After a few trips up on the lift, she got the idea, and accepted it was fine, with board behind her, instead of in front.
Then I tried her for the first time ever, to get her to ride down on the lift. She was quite a struggle to get her on, her very nervous facing the big drop in front of her, but with me walking in front, stepping backwards, as the lift progressed down, giving her lots of reassurance, we managed it, just the once. At least now I know, it is possible to get her back down too, using the lift
Arriving at the top, or bottom, there is a big wag of the tail, and a - aren't I clever.