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My name is Clare
I shall do my best to help you but I need some further information first
For clarity - will your mother be moving out?
Thank you for that
Yes this is not unusual and it is perfectly possible to do.
You will need to explain the circumstances to your mortgage broker - and your mother will need to sign a statement confirming that this is a "gifted deposit" and she will not continue to have any interest in the property.
Your Conveyancer will be able to sort this out - but it would be better to chode a High Street Conveyancer for this reason
I hope that this is of assistance - please ask if you need further details