Hello David,
I've reverted the changeset so all is now well with routing, there are no duplicated highways.

As for the query about segregated cycleway.  Regarding Way: Sheffield Road (449060625) which has the tag cycleway:both=track, (and any similarly tagged highway), the tag sidewalk=both could be added. This would then indicate that the road has a separated cycleway track and a seperated/segregated sidewalk on both sides. The tags can be adjusted (left, right, both) to suit the circumstances, the road would need to be section up to allow for any changes in sidewalk or cycleway.  Please see: https://wiki.openstreetmap.org/wiki/Tag:cycleway%3Dtrack  and https://wiki.openstreetmap.org/wiki/Key:sidewalk  for more details.

I don't have local knowledge so can't attempt such changes. If you want to have a go keep in touch via email by clicking on BCNorwich above.

Regards Bernard.