Eley cartridges.
I think you should omit the ‘british ownership’ bit, that is imposdible to know. Most larger companies have a multi national owner base.
If that is OK, then the Landrover car manufacturing. Much bushcrafting can be made using one of their products.
Not sure how long they will continue in UK, production is moving out.
owned by the indians.
I have a 30 year old defender, thats all british - got the solihull build number to prove it!
anyway, kit.
Arktis clothing, designed and made in the uk
Ghillie kettles made in the UK (kelly kettles are made in china iirc)
barbour
many small craft/cottage industries - i butya lot of beekeeping stuff and thats nearly always made in the uk (although cheaper overseas (china) stuff is available.
dunno what else