Minivator Stair lift catching on runner?

Hi, My mum's Minivator stairlift is not running smoothly - there's a panel, below the seat of the chair whiuch faces down the stairs and covers the electrics. It's attached by two screws at the top of the panel but the bottom part of the it is loose and hanging low so it is catching on the rail - it looks as though it should be supported at the bottom in some way but is no longer held in place. I have taken off the panel and re-fixed it but could not find a way of attaching the bottom part. It makes a terrific banging noise as the panel is being dragged along, catching and being pulled free as the chair moves.

Can anyone tell me anything about this?

Thanks for reading!