Could you confirm that your AXA UK policy also does not cover for airline bankruptcy only for a cancelled flight?

Though a rare case just to be sure: yes, you bought a (cheaper) ticket with a credit card and it gets refunded by charge back (I don't know: is there a time period for how long you can request a charge back?) but you have to buy a more expensive ticket if you
- don't want to lose your remaining trip bookings
- want to get home

So though an airline bankruptcy is not that common (not that uncommon nowadays, either!), it's good to know that for this you are still exposed. Yes, the title of the topic is flight cancellation policy but this is also related.