Tanner and Oak also sell a rather nice folio case, as well as wallets, handbags, a satchel and other leather accessories, all designed and manufactured in the UK. At least some of the leather they use is British leather.
Zatchels (by Leicester Remedials & Sewing Ltd.) are all made here in the UK. They make leather satchels and bags for men, women and children in lots of colours, sizes and designs with options on some bags for an additional handle, detachable shoulder strap and personalisation. They are lovely bags. Prices from £79 + p&p.