One reason for the processing being done in England could be the water quality - the same reason my kilts survived, as the water in South Yorkshire is very 'soft', it lathers easily and doesn't form a scum with soap.
There was always a box of Lux soapflakes by the big sink, all the woollen things were washed with that, carefully dissolved in warm water then the cold tap run to bring the temperature down to just tepid.

I suspect that the inner part of the kilt was linen as it was slightly glossy - polished by decades of wear.
It had a new lining made from a pillowcase and sewn in rather badly - my mum wasn't at all handy with a needle, unlike her mother who was absolutely brilliant at all sorts of making and mending.

Anne the Pleater