Although approximately on the old canal line, the underpass in the photo below had nothing to do with the canal, being built for livestock to cross under the motorway.
The restored canal will follow a revised route that will share the River Frome M5 underpass (see photos 2 & 3). The canal will be in a separate channel. However, it is likely that the new Phase 1b towpath will use this cattle underpass, as there will not be sufficent space for the towpath and canal to use the existing River Frome underpass.
Map reference for the canal & river underpass is SO 77561 06502.
(Tap / click images to enlarge)