Balance transfer layered on a balance transfer

mikeyhinde

Have had a flick through small print but can't work out what the impact of this would be so seeing if others have lived experience to confirm.

Used a 0% BT to Barclaycard for 18 months which has 12 months still to run.

They've now increased my credit limit and made the same 0% BT offer (18 month) which in theory is good timing with a 0% on another card imminently due to end.

If I take up this second transfer is it likely to cause issues in respect of the balance already on the card, so when the original 0% deal ends in 12 months and I still have a balance on the card (equal to the second transfer, after I pay off the first transfer in full), would I expect to find myself facing interest charges - or would my repayment go fully against the original transfer and therefore mean I continue to face 0% on the second transfer until that period expires (and I pay in full).