Needed to have a go at this as never actually used Spatial with force before.
Not sure if it would have been col to use google reviews and then rate them with a number? I didn't this took me ages! But I learned something new! Boom!
Loaded in a section of the Thames polyline file from the spatial package, buffered by 10m and used it in a spatial process to split the 1km trade area into North and South of the river: