Wales will kill every bit as dead as "some of wilder tracts in the western USA".
Why: Because Wales has killer combination of:
1) Heavy cold rain.
2) Cold wind.
3) No shelter.
Classic three strikes and your dead territory.
A firelighting kit is simply a waste of space.
Do you actually believe that rain, wind, and lack of shelter are unique to Wales? I can show you plenty of all three over here in the colonies and in locations that are much further from roads and other civilized amenities than anything in GB. Think Gila Wilderness, Bob Marshall Wilderness, Grand Canyon to name a few. Within all of these areas there are spots where natural fuels can be sparse, especially in the winter. It is then a good idea to carry some sort of stove and fuel, whose total weight can be surprisingly light and well worth it.
Proper clothing and appropriate sheltering material make sense wherever and whenever one goes out to play.
My comment about differences had more to do with the evident lack of fuel in Wales, an area with which I am, regrettably not familiar. On my one trip to Great Britain, I stopped briefly in the Lake District and in Glencoe. It was during an absolutely wonderful late summer and I have never experienced the storms for which those regions are justly famous for, but bad weather is bad weather the world over. I suspect there must be a difference in land use ethics between the Wild West and Merrie Old England. I could well imagine you can't just simply sit down, pull the branches off a tree, and light a bonfire... Correct?
I am afraid I would still consider carrying my fire items, all of which fit easily in the palm of my hand and weigh maybe 2-3 oz. Even more likely I would have my stove and the ability to brew up that all important Nice Cup of Tea. my British roots are still evident......