Thanks for the comments -in answer to various points:
1, Almost no pain from new knee, just a bit tight, and getting better the more i do. I think I have 160 cranks rather than 175 which i would still struggle with.
2. NCR4 from Reading to Bristol is easy, pretty and midweek when I did it almost empty until Bath. The towpath along the Kennett and Avon varies from smooth and easy to rough large embedded gravel to areas of grass...all entirely do-able on any touring bike but just hard to get much sped up consistently on a loaded bike for quite a lot of the route. The road section from Newbury to Devizes is rolling lanes and very quiet. I camped at Foxhangers below Caen Hill locks and would recommend it - was the only visitor!
3. Nomad is my first touring bike, it's heavy, so am I, so we are "steady" up the hills, particularly with camping gear. However, the Dureme tyres are great on the broken roads around here as well as gravel track and I do like the Rohloff hub. Just adjusting to a slower but more comfortable and flexible way of going!
4. Clickstand is helpful with a loaded bike, by no means a must have but not heavy.