Hi
At this point it appears to be an index reference.
The Middlesex Deeds Registry is about the buying and selling of property/land in Middlesex.
The vast majority of the population rented. If the family owned and lived in the property in 1809 you might expect some mention of it in wills left by them.
Prerogative Court of Canterbury will
Will of Edward Phillips, Tea Dealer and Rent Collector of Grove Place Tottenham High Cross , Middlesex 05 December 1843 PROB 11/1990
26th August 1808 All Hallows, Tottenham
Edward Phillips
Rebecca Walton
Bachelor and spinster of the parish
Witneses Richard Morgan and Truth Spencer her mark
Tottenham Baptisms - those after 1812 will give an address though it may only be Tottenham or it may be more specific which might give an indication of when the family moved into the property.
Edward Phillips 25 SEP 1809
William Walton Phillips 12 DEC 1814
Michael Phillips 09 FEB 1818
Emma Ann Phillips 08 JAN 1821
John Phillips 31 MAY 1827
Regards
Valda