Yes, it's also called "Permaramp" which kinda hints that it's intended to be bolted down. The spec was for a mobile ramp. (Presumably because it intrudes into work space.)
Building something that has to be self-supporting takes quite a lot more engineering.
I expect most of the cost is in certification. Workplace insurance would skyrocket (scuse the pun) if an uncertified piece of mobile safety equipment was installed.
You and your "£2500? I could do it for less!" it's exactly how managers end up outsourcing or "clouding" for bullshit reasons. You're not looking at the total costs, just the one line item.