Thank @Jilly for the words of caution.
I am cautious in nature and risk adverse when it comes to designing and building.
My wife and I have a small child so will want to rent a house during construction. I’m used to working two jobs so can do the day job plus architecting at night to reduce any unpaid time.
My vision to carry out a self build is to secure a mortgage, design for off site manufacture, then install over a few weeks to weather tight, with 1st and 2nd fix taking an additional two months max. This will reduce site management and bring all the detailing forwards in the programme.
Edit: Rates are crazy now and I don’t see any signs of them dropping significantly in the next decade, but we are building a family home, not an investment, so it is worth it to us.
However, We will switch from self built mortgage to a regular mortgage asap once PC is achieved.
The best-laid plans of mice and men….