Thank you for taking the time to respond and for your assurance of the refund of my return postage, which I look forward to receiving.
I take your word for the assurances you have received from your supplier but would respectfully suggest that your supplier is at fault here, if you take a sample pair of the gloves in question to any source of qualified opinion (maybe you could ask Hampshire Trading Standards office to recommend a lab, or find a sympatheic science teacher who will use it as a class project) or just cut into a glove and look at the composition of the outer material, particularly its backing, and apply your nose to the vapours which emanate from it, you'll realise that this is not genuine leather at all, your supplier's assurance notwithstanding. I would hope that you would want to protect your own business and would take action against the dishonest supplier, not just offer an unexamined extension of their patently untrue claim.