There are 2 main kinds of property ownership in the UK: freehold and leasehold.

A property owned under freehold is owned completely, i.e. the land and the building, unlike the property owned under leasehold where you own the building but you don't own the land.

There is also the shared ownership scheme where you own a percentage of the property as a leasehold and pay rent for the part you don't own. I think this is what is meant here with 'tenure'

Tenure: Tenancy - Miete /Mietverhältnis

The conditions under which land or buildings are held or occupied.
tenancy, occupancy, holding, occupation, residence

https://en.oxforddictionaries.com/definition/tenure

How shared ownership works?

With shared ownership, you buy between a quarter and three-quarters of a property.
All shared ownership homes in England are offered on a **leasehold only basis**.
Once you own 75%, you won’t have to **pay rent** on the remaining share.

https://www.moneyadviceservice.org.uk/en/articles/shared-own...