Just ask him if he will put it in writing (for your peace of mind?) and also ask if he will sign the form required to change the Deeds of the property from "Joint Tenants" (which will most probably show the names of both parties) to "Sole Tenant" which will only show your name.
A copy of the Deeds (if you haven't got them, although they will most probably be with the mortgage company) can be obtained on line from the Land Registry for £3.00 and then the form required (and instructions) can be downloaded for free. The Land Registry will help with any questions or requests you may have via e-mails.
Hope this helps although I think a solicitor would be worthwhile considering the value of what is involved.



