Wall Brace or Tie
This is a Victorian? cast iron wall brace or wall tie (somewhat the worse for wear).
They are more commonly seen as a simple S or X shape.
This may in fact be older than Victorian.
This is on the perimeter wall of Dysart House. The current house dates from around 1726, but there was an older house previously on the site (destroyed by fire) and also a church.
More info here.