Thank you Chris. My routing was indeed LON-SYD return, booked via Swiss directly. The cancellation on the way back was a big inconvenience and I arrived in LON one day late (24h+). Informed of the cancellation one day prior to travel, no reasons for the cancellation given (until I submitted my claim), no support with hotel booking for the extra night in SIN, wasn’t communicated my rights as a result of the cancellation, rerouted directly to LON instead of ZRH, moved me around from one airline (LH) to another (LX) after I’ve already checked in without informing me in advance.. all I got from them was the standard apology for the inconvenience caused and now the ‘you don’t qualify for compensation’ bs. You’d expect at least some attention given to a SEN during IRROPS but In my case it was a complete, unapologetic, mess.
I do plan to claim in the UK under EU261 as you suggest and will take them to court if necessary.
Funny enough I had another LON-SYD routing booked with them in C/J for January. I cancelled that now and rebooked with OS/TG and SQ/LH instead. I won’t bother with LX on non-EU flights anymore. This loophole and how it’s being exploited by them is absurd. Shame!