I ran this route in reverse, ie Hunstanton to Lyme Regis meaning the majority of the elevation was in the last 3 days as I crossed Dorset. I was sent supported for the first 5 days then supported for the 2nd half. The route is great, however the Wessex Ridgeway is the least well marked trail and the GPX file is not particularly accurate but I got it done in 10 days. The other three national trails are well sign posted particularly the Pedlars Way and the Ridgeway.
I averaged 60km per day with in excess of 9000m of elevation, stayed in pubs for the first 5 days then camped with my support crew. It was a brutal test of endurance, ive set a time which is no doubt beatable, if anyone wants to give it a go I suggest hiking the Wessex Ridgeway first to familiarise yourself with the route as its not always obvious. Also there are a lot of angry looking cows in that section to which added to the challenge!