Thanks for your enquiry.
The private mortgage is of course required, to protect your financial interest in the property. As the property is to be purchased in your Daughter's sole name, only she will sign the CH1. Hence, it will indeed be necessary for her partner to sign an Occupiers Consent/Deed of Postponement,as he will not be bound by the terms of the CH1 and by signing, it is giving you the required protection in the unfortunate and unlikely event of a dispute in the future.
Therefore, your Daughter's Solicitor is correct in what he is doing.
I hope this clarifies matters, but please let me know if I can assist further.
Can I assist any further?
Hi, can I assist you any further? Kind Regards Al