Informal changes to shares paid

You and your co-owners can agree to divide shares differently to what the Title Deeds say.

Ideally you should all sign an agreement that this is what you will do. This will then form a contract between owners that can be upheld in law.

However, if one owner sells, the new owner is not obliged to keep to the same arrangement.  You can only make a change binding on incoming owners if all owners change their Title Deeds.