I was driving south towards J4, and was exiting to the right, onto the A406 westbound. Here's a permalink (I think) for the start of the junction: https://www.waze.com/editor/?lon=0.0442 ... 33&env=row

Note that at this point, the road forks into a left and right line. A few hundred yards further on, the right lane can go either east (by keeping left) or west (keeping right), but the left lane can only go east. On waze, the junction is marked at that later point, by which time it's far too late to join the A406 westbound if you're in the left lane; the verbal instructions are also therefore misleading, as they miss the first fork. So the split should be made at this first point, not the later point. Or if it's feasible, have two splits, a new one at the first forking point, and retain the existing one for the right hand lane, the left fork of which then joins the left fork of the first fork. If that makes any sense!

Thanks!