Thanks  for that, As far as I can see it has no designation, except signage for a restricted byway. but as the application was for a bridleway, I used that instead. I've deleted that designation. My logic at the time was :
 1. On the o/s map at Bing.com it is marked a a road called Long Lane.
2. It looks like a single carrageway track.
3. The reference M279 LH on maps.cambridgeshire.gov.uk/mycambs.aspx for this route, has no link, and refers to a different path 500m to the east, although it may be that details for this route are just not published.
4. The Cadastral Parcels do not cross it - like a road,
5. It looks like a byway of the sort locals hate as it will be misused as a race track.
6. Applications of this nature are often not resolved for many years by under budgeted councils.
 For those reasons I have left it as a track, seasonal, or requiring a permit. If you think thats wrong, I  am happy for you to change it.