Julie - such things can be confusing as whilst filling in and submitting paper forms can seem simple it's really a case of understanding what's actually required and why first. Then things can be a lot clearer.
We register the legal ownership and not the specific 'shares' you refer to for example. And the legal ownership is only ever transferred as a whole, so 100%
Form TP1 is used to transfer a physical piece of the property such as part of the garden. It's not used to transfer a 'share' in the scenario you describe
Are you trying to transfer the whole of the legal ownership from the two of you to just you? And if so how is his 25% share going to be protected?
If the ownership is already joint and there's a form A (joint ownership) restriction on the register then you may not have to do anything with us. The change in % share in the beneficial ownership (value) isn't something we include on the register -
Joint property ownership: Overview - GOV.UK
These are Qs you should both get legal advice/assistance on as the answers will then help you understand what forms are needed and how to apply
Land registration is complex, designed to protect legal and financial interests in property. There can be significant consequences for any error. Please consider seeking legal representation. Find out about
making an application without legal representation.