Layer Estimates:

Layer: B3 Mastermap Text (ID:0)
Count: 60
Extent:

XMin: -358582.752606514
YMin: 7551675.522896
XMax: -357437.506884533
YMax: 7552533.11749746
Spatial Reference: 102100 (3857)

Layer: B3 Mastermap (ID:1)
Count: 499
Extent:

XMin: -358641.77609489
YMin: 7551562.96474073
XMax: -357418.248282794
YMax: 7552570.60607343
Spatial Reference: 102100 (3857)