What you have is an estate rentcharge. That is basically a covenant on a freehold house that allows someone to collect money to pay for management of the communal parts of the estate.
It is analogous, but not the same as, service charges on a leasehold property. Confusingly it is NOT the same as a 'regular' rentcharge, which is just a fixed sum of money payable to a rentcharge owner and the legal implications are very different.
Estate rentcharges have been used for many years as a mechanism to pay for this kind of communal management. In practice they mostly worked ok, although they had one problem in that there was no effective regulatory/judicial oversight of how they functioned. In the case of a service charge for leasehold properties, you can always appeal to a Tribunal if you think you are being charged inappropriately. Many estate rentcharges are actually owned by a Residents Association, so there was little incentive to mismanage in those cases, but some were owned by third party corporations, not all of whom were above-board.
However a bigger problem then arose as a result of a legal case - Roberts v Lawton (2016) aka 'the Morgoed case'. Morgoed bought a bunch of estate rentcharges and looked for instances of non-payment. They then took someone who had not paid and then attempted to take legal possession of a title to their home on the basis of some clauses in the Law of Property Act 1925 (Section 121 specifically). For decades no-one really thought the courts would allow this, but it turns out they decided it was the law, even though they described this as 'draconian'.
So, over the following years, mortgage lenders started to realise this issue and increasingly they now refuse to lend on properties unless those Section 121 powers are modified/removed. The specific problem is that the mortgage lender has no opportunity to be notified of any non-payment. In a leasehold property, they must be told - to protect their security, they would then pay the service charge or ground rent themselves, add it to the mortgage, and hit the borrower with penalties or even take possession themselves. They don't get to do that with an estate rentcharge, so they could end up with a mortgage that isn't being paid and no opportunity to repossess the property.
That is why the DoV in your situation is critically important for your buyers.