Sorry to hear of the hassle you've had/are having, I sympathise. Sadly too late re that item, but I've learned that murphy's law means if you want something fast it'll go wrong (or in your case, very wrong).
eBay's Estimated Delivery Dates are just that - estimated. Experience has made me sceptical of them at best, and mostly disbelieving at certain busy times like the run-up to Christmas. I myself would contact a seller BEFORE buying, explain I'd like the item fast, and rather than rely on standard EDDs could they please upgrade the postage, ask them to send an invoice for it.
Most sellers know some buyers want faster shipping and for some accommodating that can turn a new buyer into a repeat buyer. Sadly with your item they've lost a buyer, something they could've predicted given the "stock" issue! You say: "The supplier tried to say the 3-5 days was the UK delivery time after they had received it. That's not in anyway acceptable." - I definitely agree with you. Maybe they should be reported to eBay for misrepresenting eBay's dates - it's a misrepresentation that eBay wouldn't want anyone to do again or for it to proliferate. If they said it using eBay's messaging system, eBay can see for themselves.
Anyway, if you ask before you buy and a seller can't help with faster shipping, then you'd know in good time. This should work with most sellers.
