It looks like a good idea.
Now you have seen a picture of the product do you think you could get it cheaper if you made it yourself?
Socket, 15amp cable, fuse holder and four terminals. By the looks of things you will have to bore a hole in the cover, that's not a big issue
On the other hand you can get bar raisers with a plug already. I never thought I would use/ like them. Get a set and wow.
It looks like a socket and a piece of cable with a fuse. Std socket PS-001 $16.00. Or PSO-007 includes cable and socket, still only $24.00. Even if you cut off the plastic plug and solder more cable onto the tail, it still works out cheaper that $45.00
I like to investigate things, sorry to put a damper on things. My Scottish heritage has made me frugal.