Layer Estimates:

Layer: Rivers (ID:0)
Count: 257
Extent:

XMin: 343680.29
YMin: 660975.5
XMax: 379468.81
YMax: 685807.619999999
Spatial Reference: 27700 (27700)

Layer: Rivers Buffer 250 (ID:2)
Count: 1
Extent:

XMin: 343430.3901
YMin: 660725.525
XMax: 379718.81
YMax: 686057.595000001
Spatial Reference: 27700 (27700)

Layer: Rivers Buffer 500 (ID:3)
Count: 1
Extent:

XMin: 343180.3901
YMin: 660475.525
XMax: 379968.81
YMax: 686307.595000001
Spatial Reference: 27700 (27700)