It would be extraordinary, though possible, if fellow leaseholders could invoke forfeiture but the freeholder could not. That would be incredible, and I am sure it would have all its own problems.
The point remains that, if you keep some kind of forfeiture, freeholders will want to keep hold of that power, because it is exactly that: an unfettered, threatening power, which leaseholders speak about as though it is mythical, like a dragon that will burn you if you stand up to the freeholder. Words fail me when I try to describe how forfeiture must go. We have had many conversations in which the word “feudal” has been bandied about. This is one occasion where it has real meaning. Forfeiture should and must go.