Leasehold is a property right whereby you use someone else's land (e.g. the local authority) as if you were the owner, but you are not the owner of the land.

The ground rent or canon is the annual or periodic fee you pay to the landowner for the use of the land.

No, a leaseholder is not the owner of the land or the house built on it. However, the leaseholder is often entitled to compensation for the value of their house if the leasehold ever ends. This means that it can be resold for a substantial amount. Ownership of a house on a leasehold plot is only possible if a right of superficies is also established.

In some cases, yes; in others, no. This depends on the policy of the local authority or other leaseholder. Some local authorities have regulations in place for purchasing bare ownership.

That depends on the agreements you have made with your ground landlord. Sometimes a ground rent increase can be prevented or the demanded increase can be reduced. For example, ground landlords sometimes use contracts that are unreasonable, so that parts of the contract can be rescinded by the court. Errors are also relatively common when calculating ground rent increases, so it is necessary to check these types of calculations.