It's not formally unnamed, as it has Designated Street Name USRN 37011041 and it's recorded in OS Open Names as "Church Path". If "Diagon Alley" is the local nickname, it would go into the loc_name tag.

If there is a 10% incline on part of the path, it might be better to split it and apply the incline to just that section.

How does the path cross the stream flowing through the woods - is there a bridge?