From the UK CAA website;
Flying
When the applicant holds a current and valid pilot licence for another categories of aircraft they can be credited with flight time up to a maximum of:- for TMG or sailplanes, 30 hours flown as PIC;
- for helicopters, 50% of all the flight time requirements for the issue of an ATPL(A).
Holders of a UK issued flight engineer licence may be credited with 50% of the flight engineer time up to a maximum of 250 hours. These 250 hours may be credited against the 1500 hours of total flight time listed above and the 500 hours multi-pilot operations requirement above, provided that the total credit given against any of these does not exceed 250 hours.
The experience requirement shall be completed before the skill test for the ATPL(A) is taken.
Although Ultralight, Light Sport or Microlite aircraft aren't mentioned they presumably aren't intended to be excluded.
Last edited by Fl1ingfrog; 11th Apr 2023 at 19:27.