Hiya, thanks for trying to improve the map!

Unfortunately your change here is not correct: the access=private tag sets the default tagging (including access for vehicles, bikes, horses, etc.), and the foot=designated tag then takes priority over that, so this path was already correctly marked as accessible to the public on foot.

See https://wiki.openstreetmap.org/wiki/Access_provisions_in_the_United_Kingdom#Public_footpaths and https://wiki.openstreetmap.org/wiki/Key:access#Transport_mode_restrictions for more information.

What was it that brought you here trying to change this particular path? Is something not working somewhere else? Ta