Not to be a party pooper, but covenants are a technically complex area of law. I would steer clear of Wikipedia, for your sanity’s sake. To summarise the position (in extremely general terms): Positive covenants don’t run with (or “stick to”) the land in the same way restrictive covenants do, but they can be passed down contractually to successors in title through deeds of covenant to indemnify the performance of the covenant (this forms the “indemnity chain” I mentioned previously). By way of illustration, this means something like:
B promises to pay X to A
B sells to C and C promises to B that if A asks for X then C will reimburse B
then C sells to D and D promises to C that if A asks for X then D will reimburse C who then reimburses B (etc etc).
These indemnity covenants are noted on the title register - each one would have been part of the wording of the deed of transfer when purchasing the property.
A complicating factor is what happens when land which is burdened by a positive covenant is sold in part - without a deed of indemnity, would the positive covenant continue to burden the new parcel? I suspect not, but I’d be interested to know what OP’s legal advisor says in due course. The legal analysis on this scenario can’t be performed except by OP’s legal advisor, who will have all the information needed.
As an aside, I can think of a number of instances in law of enjoying the benefit of something without paying for it - think of a freehold first floor flat which benefits from the right of support from the flat underneath. They won’t be automatically required to contribute to the ground floor flat’s structural maintenance! So I think that the idea of maintenance being linked to enjoying the benefit of the structure is probably a red herring.
Let is know how you get on, OP.