As a condition of planning consent, the developer who built your house must arrange long-term management of the open spaces and features. The developers' preference was for Greenbelt to take on ownership and the associated obligations.
Planning conditions require homeowners to contribute to the cost of managing this land, so that everyone who lives in the area can continue to benefit from the local open spaces and features.
The design for your development, approved as part of the planning process, will include open spaces and features that will require long-term management and maintenance. The developer who built your house has arranged for Greenbelt to carry out this maintenance for the benefit of the development.
The relevant homeowners on the development contribute to the costs of this management and maintenance to ensure that the open spaces and features are maintained for the lifetime of your development.