We did a self build. Bought a plot, had an architect design a bespoke house. We then got a specialist company to build the structure of the house on site, and trades to do the interior. It’s highly insulated, triple glazed, etc. It took 8 years from buying the plot to moving in.
I won’t go into all the horror of it here 😊 but I definitely wouldn’t do it again. We had a nightmare with the planning - the application got through easily enough, but a neighbour suddenly became very unhappy when the house was going up and instructed a solicitor to make the local authority withdraw our permission. The local authority was hopelessly inept, and tried to do this. We spent a lot of money on lawyers, fighting a legal action. We were successful, and the permission stood - but it was horrendous.
Also, we couldn’t get any local trades to work on it - joiners/plumbers/electricians - because the structure was not standard construction, and outside their comfort zone. It felt like we were being exploited and ripped off a lot of the time. The specialist window company was totally inept, and we had to wait 18 months for the windows - with the build paused - because they were shockingly incompetent.
We were unlucky, and know two other self builders who have had good experiences - but they were hands-on people who did all the interior fitting out work themselves. It was obviously a lot of work, but they retained full control and could get things done without getting ripped off.
On the positive side, hopefully we have made some money as the house will be worth more than we spent. Also, our heating bills are very low which is brilliant at the moment.