GMP Baird Ltd & Ors v Revenue and Customs (VAT - allegation of supply chain fraud in scrap deals - Kittel and Mobilx - knew or should have known - heightened awareness of fraud when trading in scrap metal - cavalier attitude towards due diligence - consideration of all of the circumstances of the purchases - no means of knowledge) [2025] UKFTT 1540 (TC) (11 December 2025)