Some golf courses are unenclosed and fully public.
From https://www.thesocialgolfer.com/golf-courses/united-kingdom/london/chingford-golf-course:
“It is public space, so there will be dog walkers, non-dog walkers, cyclists etc. about. But they seem friendly enough and keep to footpaths. Just be aware.”
In Chingford this probably comes about because it’s part of Epping Forest. The Epping Forest Act 1878 dedicated “uninclosed parts thereof as an Open Space for the recreation and enjoyment of the public; and for other purposes”. That it seems allows the Epping Forest Corporation to provide (and, I presume, charge for) golf courses using certain parts of the forest, but did not allow them to exclude the public from those areas to use for other purposes.
The same may (or may not) also apply to some other golf courses where the land itself is unenclosed public property with covenants preventing enclosure or exclusion of the public.