Any suggestions where to buy box profile steel cladding for the flat roof of my Gentlemans inventing shed?

This is the sort of stuff i’m after –

Box profile steel cladding

Ideally plastic coated a colour, rather than galved, and i’d like the angled steel trims to go along to sides/top.

I’ve priced it up from the mob above and it comes out at around £600.. feels a bit dear to me…

Where are you. Cheapest two places I found were in Leek and Ashton, but I was looking local to me.

I got some from Broxton Gates in Cheshire.
Don’t know if they are cheap, was just convenient.

Broxton Gates

We get our agri store (Mole Valley Farmers). Can’t remember the cost but it’s not a lot really and I don’t think it was much different to the prices up at that place tbh, it’s not expensive. The advantage of that place you have posted is they will cut to the lengths you want so you will have a lot less waste and hassle of cutting and you get to choose the colour (will save that link as it might be handy)

Are you sure you have your calcs right? What size is the roof?