Thanks for the reply! Highdown Rise has a separate footpath on OSM just to the east but it looks like little more than a worn line in a field so don't know how 'official' it is. I agree that one set of users shouldn't manipulate the data so to have an adverse effect on everyone else, I will have a look at CiryStrides forums and see what others are doing in similar circumstances.

I'm a citystrides.com user which gets its data from OSM, Titnore Lane is now showing as the only incomplete item in Worthing so I copied the profile of adjacent Highdown Rise, 'no pedestrian access'. The alternative is I complete the item by running the length of Titnore Lane, its unlit but will be quieter at night, what time of day would you recommend?