You can’t transfer directly between ISAs and non-ISAs.
It’s not possible to move money directly between a non-ISA and an ISA account at maturity, as they’re treated differently for tax purposes.
Here’s what you can do instead:
From non-ISA to ISA: Withdraw your funds when your account matures, then open and fund a new ISA (subject to annual ISA limits).
From ISA to non-ISA: Withdraw your ISA funds at maturity - but keep in mind that once withdrawn, they lose their tax-free status.