Hi all,
Sorry for the delayed reply, I've been occupied with drawing bridal gates and stiles before I can get back to this model!
All of the info/options you've provided look spot on, I'll have a look through all of the various links and also try to go back to the topo contractor for the spreadsheet of info as I'd like to try both methods if I can.
In case anyone is interested, the topo data is of a Byway (BW) which i'm tasked with repairing/ resurfacing and installing sufficient drainage (working with drainage team) to mitigate the water erosion and damaged caused by 4x4 vehicles. I've floated the idea of bringing the levels back up on the BW to a similar gradient as the natural slope of the hillside to allow the water to run off in the direction it would have prior to someone bench cutting a big track down the middle of it.
Thanks again for all of the great advice, i'm sure i'll be back with another question regarding 3D modelling existing terrain and layering proposed improvements clearly.
Cheers