Layer Estimates:

Layer: Historic_Counties_2ndEdOS_v1.0_(WGS84)_RCAHMW_ply (ID:0)
Count: 16
Extent:

XMin: 166704.150033818
YMin: 164137.183805042
XMax: 356925.164847291
YMax: 398453.148885937
Spatial Reference: 27700 (27700)

Layer: Historic_Counties_Merged_2ndEdOS_v1.0_(WGS84)_RCAHMW_ply (ID:1)
Count: 13
Extent:

XMin: 166704.150033818
YMin: 164137.183805042
XMax: 356925.164847291
YMax: 398453.148885937
Spatial Reference: 27700 (27700)