This was our first visit to Berwick and we picked up details of the town walls tour from the Tourist information website. Both my wife and I have an interest in history and have been on many walks and tours of one form or another.
But we were pleasantly surprised by the depth of research that had gone into this tour by our tour guide and the way he was able to communicate so clearly to all of in in the group. All but two of the people on the tour had a keen and informed interest in the history of the borders and were keen to find more of the role of Berwick in it. So there were many questions as we went round the wall - all happily fielded by Derek Sharman. There was so much discussion that our tour lasted well over two hours - Quite delightful and totally engaging.
The tour itself is easy walking, on smooth paths. There are some steps but my feeling is that iff there was a need to structure the tour for wheelchair users it would be simple to arrange with a bit of prior discussion.
On our way round we were taken into one of the bastions, explored the gunpowder store and were shown one of the ice stores used to keep the ice into which fresh salmon was packed before being shipped to London. So we had much more detail than could be experienced when simply walking round - although the walls are plentifully supplied with detailed information boards.
A really good, inexpensive (£7 per person) tour.