Interested to know you're ex-army too, Graeme. Like me.
Anyway, you've started something. Dave and I are planning a pilgrimage too now! Rochester to Canterbury. A lot less than your proposed journey! It's about 25 miles along a main road or we could go the "Pilgrims' Way" along the North Downs, which is quite a few more miles but is much more off-road. We think it would be better to be on a recognised walking route, maybe meet other people, and stay in places where they're geared up for "pilgrims".
My reason for doing it is that a nurse told me that the best thing for my back and hip (after various injuries) would be weight-bearing exercises such as walking and I've been pretty much housebound (unless taken out by Dave) for too long now. If I could do this journey it would give me a whole new lease of life. We were thinking along the lines of walking maybe 10 miles a day, stopping at a B&B, then 10 miles the next day... and so on. Then we could get the train home at the end.
I don't know if 10 miles a day might be a bit ambitious. I used to be able to do 40 miles over rough terrain without even thinking about it, but now it's a struggle just to walk around a shopping centre without a trolley to lean on. My legs and hip are fine it's the back pain that's the problem.
Anyway, I tried on my old (maybe 25 years old?) boots - three season boots - and it seemed obvious to me that they're too heavy and rigid for this venture, even though I used to wear them all day every day sometimes. They're also rather tight now. So I now have a brand new pair of "light hiking boots".
Goodness know what training I'll have to do for this because I don't think I can just set off and hope to achieve the 30+ mile walk without doing something beforehand. Maybe a couple of miles here and there first. That in itself would be a benefit.
I'm not sure why Dave wants to do it - probably just for the sake of doing something different.
Oh well, we'll keep you informed of our progress or otherwise. The main thing for me is that it's something to look forward to.