Other than Ireland, which is treated as part of the UK for the purposes of travel restrictions on return, and which imposes no restrictions on fully vaccinated arrivals from the UK, no.So fully jabbed still can't go anywhere at no extra cost? I.e only have to present your proof of vaccination. I have a lft kit at home. I can use that before departure and after my return.
You can't use a free NHS lateral flow test for travel. You'll be denied boarding without proof of a negative non-NHS test, and can't complete the passenger locator form without a booking reference for a private test after returning.