I'm looking at possibly building my own house in the next year or so. Basically, I have the opportunity to acquire a decent sized plot of land in Suffolk (no planning permission yet) and I want to give someone about £150K and let them competely design, build and fit a house out for me so I can just move in at the end without any messing. Probably a small 3 bed chalet bungalow or something. I have absoutely zero knowledge or experience of the subject or even the costs so if you're a builder or you've built your own house I'd be grateful for any advice.
I've also been looking at pre-fab houses such as the ones here: https://www.dan-wood.co.uk/en . Has anyone here used a built a pre-fab house? Any down/upsides? Especially when it comes to resale.

Thanks in advance!