Seems like a genuine saving on a highly-regarded product. Here's the blurb if you can't be bothered to click the link:
Suitable for heights up to 3m (9 10)
Minimum loft opening size (L X W) 0.508m x 0.406m (1 8 x 1 4)
Minimum storage space 1.12m (3 11)
Minimum clearance arc 0.71m (2 4)
Handrail for added safety
Unique friction guides for smooth & easy operation.
Suitable for professional and domestic use