Simon - This could add further confusion to your quest, but I've found the following:
1821 Marylebone census
WESTERN living in Charles Street, High Street [page 66]
1831 Marylebone census
WESTERN living at Margaret Street [page 311]
WESTON living at Castle Street West [page 88]
WESTON living at Gloucester Place P.S. [page 221]
WESTON living at Nelson Place [page 354]
WESTON living at Great Park Street [page 423]
WESTON living at Spanish Place [page 507]
