At http://archaeologynewsnetwork.blogspot.co.uk/2014/02/ancient-iron-workin… … this story caught my eye because a friend of mine has discovered several bloomeries in what is nowadays an isolated woodland environment on a high slope above a valley in the Chilterns. In the Bronze and Iron ages this valley would have been lined with farms, and in the Roman period it is known there was a string of villas all the way along the valley bottom. The upland area may not have been wooded then, a situation that in the post Roman period developed into manor estates with manorial waste on the slope (wood pasture, heath and common). As common land it was the sort of place that itinerant industries prospered without too many restrictions – and several bloomeries have been found, as well as enclosures, Roman coins, pottery, and pieces of iron slag, and medieval pottery too. In all likelihood the iron working is medieval – but it could also date back to the Roman period, or earlier. It must have been a common practise, anywhere that charcoal could be produced (to provide the necessary heat, the iron itself being brought from a far source).
In the link above the iron working has been found in Sussex, during road construction between Bexhill and Hastings. The site is just one that has been uncovered – but the only one with evidence of iron working. Other sites display evidence of Mesolithic activity, and tools and pottery from the Bronze and Iron ages, and the following Roman, Saxon and medieval periods. A lot of archaeology has been uncovered. The iron working is being dated between 50BC and 50AD – but I suppose this may change.