Positive it's been returned. I'm out a revised total of £2.5k, as of today, on declined but still charged transactions with a billing date looming at the end of the week. I consider that it is appropriate for me to dispute them all, otherwise I'll end up funding the £2.5k until I burn off the resulting credit that would likely arrive in 2 weeks after the billing date. Once this gets sorted the concept seems good provided the card limits (not cash ATM, just ordinary merchants) are increased. I'm not sure I follow there is any credit risk as the underlying card has to approve the charge, so curve should never end up with non payment as that risk lies with the funding card issuer. I fully admit to not knowing the complexities of funding risk on this scenario with 1 card being funded by another card.