Many thanks to Paul and Chris for their contributions to this thread.
If I can just correct one minor but important error, the correct generic name for pottery produced in North Devon with river gravel inclusions is 'North Devon Gravel Tempered Ware', and not as above.
The work carried out by the Exmoor Iron Project at Brayford and Sherracombe Ford under the leadership of Dr. Gill Juleff has certainly helped to rewrite the history books regarding North Devon. The work in Combe Martin on silver/lead smelting is also redating much of our previous knowledge and I am personally very gratefully to English Heritage for the quite amazing amount of time and effort they have put into research and analysis of the 16th/17th century smelting debris I have discovered here. I cannot fault EH and its officers for their encouragement, enthusiasm and willingness to 'stick by me' on this project.
Paul raised a very interesting point when he enquired where the future ceramicists are going to come from, especially for medieval and post-medieval ceramics. It may be that the answer to this question must lie with local North Devon Archaeological Societies and Historical groups. If we were to combine the resources of NDAS, (North Devon) TAG (Tiverton) and ACE (Winkliegh) - 230 members in total, and the plethora of Historical groups in North Devon - I have spoken at 5 such groups - 400 members, then we must have a powerful lobby, and enough willing hands to get something off the ground ourselves.
At every excavation at which I am involved in North Devon, I now keep accurate records of the contexts from which NDGTW comes, and the styles, shapes, glazes and fabric of the pottery. This can be laborious work, and you end up with a hell of a lot of sherds, but it does mean that gradually you can build up dating evidence from association with other materials - clay pipes for example for which North Devon has excellent dating evidence. All I need now is a good database that will hold all the relevant info. Any ideas anyone?
PS. Chris - Spoke with Jim Symonds - the Sheffield culverts are rather different to here, but worth pursuing.