The filter when new comes as a kit with 2 small brass olives, and nuts. The nut is slipped on first followed by the olive, and once the filter is placed in position and the nuts tightened, the olives compress and tighten on to the filter spigots. Once that compression has occurred, the only way to remove the nuts it to cut them off, and the olives are not re-usable.
I think I bought my replacement filter from Melvyn Rutter, though Brands Hatch Morgan advertise them too.
https://morgan-kent.com/product/fuel-filter-8-1968-86-carb/
