Yea I've watched a few of them, you do wonder if it's just some baloney or it actually works. There are several UK businesses seemingly offering such services. Google slab lifting or similar.
I think you'll be fine adding corrugated sheets to the existing rafters, no need for anything else assuming it's been well built ad you use the proper fixings. I daresay there may be the odd leak but with a bit of luck the leak wont drip directly into your G&T.
Kitchen cabinets are melamine covered, they can be painted with appropriate products.
I have some (Ikea) Billy bookcases to paint at some point which are also melamine covered, my research eventually had me speaking with Zinsser, they're recommendation is as follows:
1. Wash them with hot...
Let's get this straight, rather than a continuous loop of chain the blind has one chain but broken, effectively. Presumably one end you pull and the chain goes down, you pull on the other end and it goes back up. Presumably at no time can the end of each chain disappear out of sight into the...