Requesting advice here - I'm due to fly LIS-LHR-DOH-SIN on Saturday, starting with BA519 (arr LHR 1920) to QR16 (dep LHR 2155). Normally I'd be comfortable with this connection.

The ticket is a DONEx issued by BA.

Is there anything to be said for trying to move the LIS-LHR to the early (0710 - BA499) departure? The change is free by fare rules, there is D class availability on the LIS-LHR but I'm not sure if married segment logic will deny it, rendering the point moot.

I only ask as QR shows scant availability to SIN on the 16th, as does BA on their direct services. A 24-30 hour delay in arrival to SIN is acceptable, but a longer delay must be avoided and the cost of a day room at LHR on the 15th is worth it in that context.

On the 'against' side is the minor inconvenience of getting up earlier, and the chance that the BA499 is cancelled and later flights fill up. I'm not sure if there's any discernible pattern to proactive short-haul cancellations which would indicate a more reliable option.