Layer Estimates:

Layer: B4 Mastermap Text (ID:0)
Count: 51
Extent:

XMin: -360862.507862139
YMin: 7549446.91988808
XMax: -359976.910720862
YMax: 7549933.76125943
Spatial Reference: 102100 (3857)

Layer: B4 Mastermap (ID:1)
Count: 513
Extent:

XMin: -360926.331016472
YMin: 7549370.15543556
XMax: -359928.535111416
YMax: 7550016.71190191
Spatial Reference: 102100 (3857)