You will see from the videos that we did not discover anything that wasn't already marked up on the drawings.  Importantly the stretch under the access road - which we have estimated on a speed, time and distance basis and extended to a roughly 30m stretch (to cover off any timing errors on that) - all looks good at the moment. 

We encountered a signal range challenge because of the difficult access at the South end, so were not able to get to about 50m of the total culvert length.  We managed approx 200m from the North though, with good signal strength all the way.