To forestall another moan, this is highly unlikely to be covered by travel insurance. This was not a connection and there are few policies which would cover two entirely separate journeys on two tickets. OP should read his travel insurance policy carefully.

OP is lucky that it happened on the outbound with cheap onwards tickets. If that had happened on the inbound and presuming that OP's F tickets are not in full F and thus refundable, this might well have resulted in having to purchase new single tickets back to the UK.