These two products are slightly different. Self-build mortgages are for applicants who want to borrow the funds to build their own property. Like development finance, the cash is released in pre-agreed stages following an inspection.
New build mortgages apply where a buyer wants to purchase a brand new development. This can be more complex, although if you are eligible for a government mortgage scheme, you will be more likely to be successful since most such initiatives are targeted at new-build developments.