A useful table from Homebuilding and Renovating sums up the latest deals for April. As they explain:
Self build mortgages work by the lender releasing the loan in stages as the new house is completed, up to a certain Loan to Value (LTV) of the total overall cost. Common stages are plot purchase, foundations, wall plate, weathertight, first fix and completion. Mortgage rates for self build tend to be a little bit higher than those for conventional property mortgages. Lending criteria – how much you can borrow – will be judged on affordability in the same way as a regular mortgage. Commonly, most self builders convert their self build mortgages to regular property mortgages once the project is completed.