After many questions and chats, here are the two examples of Iron Age clothes I use myself when portraying crafts and life around 300200BCE, both based on finds from a bog in Denmark (original in Mational Museum of Denmark):

the Huldremose Woman's ensemble.
(a woolen skirt, a woolen shall, 2 sheepskin cloaks that I don't have replicas of yet AND an undertunic made of vegetal materials, be it linen, nettle fibres or else. This is the newly discovered element: the Huldremose Woman being a bog body, all vegetal fibres have been eaten away by the acidity of the bog. But on her thigh researchers found a print of a woven fabric in vegetal fibres... prooving she wore an undertunic / undergarment that has simply disappeared in the bog, protecting her skin from the wool and the wool from sweat and dirt... as it seems to have always been the case through history!)
I added shoes found in another bog from roughly the same time period, and woolen hoses / tall socks made of fabric copied from an italian find from the mid Iron Age. I believe many people whould have been barefoot in shoes or without them, depending on jobs, season, weather etc... but I, as a modern period interpreter, need my socks in the winter!

the Huldremose Peplos.
Found in the same bog as the above, but not in connection. It's not seen as a 2nd garment belonging to the same lady! Also.. it could simply be a piece of cloth and not a peplos. It could be a mattress bag for all we know: It has been found in the 19th c. and ... washed. dried. ironed... before being sent to the museum and curators of the time. So the folds shown in the museum photos have been ''made'' for the display maaaany years ago not found on the garment. Big difference!
Anyhow there are many depictions and mentions of Iron Age women around Gaul, Germania, Dacia, etc wearing a peplos or ''tube dress'' like this. Over an undertunic made of vegetal fibres MOST probably: it's both logical, has been done for millenias and is the case on the Huldremose Woman's outfit from the same spot and same time period.
...
one day I'll do a video about hair styles too ;)

When is the Iron Age?
''Iron Age'' in Britain is usually 800BC to 43AD, date of the Roman conquest by Claudius. In France, 800BC52BC (battle of Alesia and Roman conquest).
For me... well... there is a very early iron ring found in Scotland dating back to 900BC, and I consider 52BC as the ''end'' of the Iron Age as I come from France myself!
So here: 900BCE to 100BCE is what I research mainly in terms of ''Iron Age'' life. Before much Roman contact with Britain. But eh, you do you ;)

Video from BUTSER PLUS:
This video has been made for the online platform ''Butser Plus'', at Butser Ancient Farm in Southern England, by their own filming team.

Find many more videos about ancient living, various traditional crafts, rare breed animals and experimental archaeology, presenting many time periods, on www.butserplus.com for the price of a coffee or a monthly donation to support Butser Ancient Farm's work.