This approx. 5 mile walk from Mere to Gillingham takes you along an old drove and up over Bowridge, taking in some glorious views. It enters Gillingham via the Bay area, giving a very different perspective on the town. A short stretch was quite muddy – not impassable, but you might benefit from some sturdy footwear.
You can download a gpx of the Gillingham to Mere version of the route at https://beta.slowways.org/Route/Gilmer/130 You’ll need to reverse the gpx route if you want to walk from Mere – you can do this via apps such as ViewRanger (free), but not via OS maps unfortunately.
You can find more information about buses back to Mere to help plan your trip if you don’t walk to walk back.