A friend of mine also suggested Lines to Point, then Points to Continuous
Anyway...
1) I bumped up the number of points via ArcMap Options and tried TopoToRaster again - FAILED! Maybe there are some of the options I should tinker with? See attached image
2) Dice - I'm sure it done something but I took it to 750,000 and re-ran TopoToRaster but FAILED saying "too many points in the contour polyline" so I diced it further to 500k, 250k, 100k and then to 10k at which point TopoToRaster WORKED
Thanks for the help
Dean