Just to report a successful claim under EC261 for a delayed AY flight.

On 25th January my wife and I were scheduled to fly SGN-HEL-LHR (the return leg of our booking on one PNR). We live in the UK. The incoming flight to SGN was late arriving and I was sent a text by Finnair saying the reason was "technical" (but unspecified). En route one of the FAs told me that the HEL-SGN went tech after the flight had boarded but couldn't be fixed. Apparently a substitute plane and crew were put in place (I've no idea if this is all correct btw).

In the event, we were 3hrs 55mins late into HEL at the gate (that 5 mins must have saved a few euros!). However this meant that we missed the last possible connection to LHR and AY booked us into the airport Hilton and the first available flight next morning - all the documentation was ready for us to collect in the service area in the baggage hall - all very efficient!

Next day our flight to LHR went without incident (although late). Overall we were 11.40hrs late into LHR from SGN. On 29th Jan I filed our claim for 2 x EUR 600 and today, after a couple of earlier prompts, I was notified that our claims of EUR 600 each will be paid as compensation.
We have also been offered EUR 800 in vouchers as an alternative. We might well take the vouchers but I am clarifying a couple of things with CS. Can Euro vouchers be used to pay for flights in £ (ie booked from the UK)? Reading the thread here I think the answer is yes! Also can voucher paid flights earn Tier Points and Avios on Oneworld BAEC?

Incidentally these were our first ever AY flights (each leg on an A350 - but booked by me to be so!). The only flight anything like on time was the initial LHR-HEL leg. Apart from the severely delayed SGN-HEL, we were 2hrs+ late into SGN and 1 hr+ late HEL-LHR. Nevertheless we would be happy to fly AY again - we liked the planes (we were in Business), and the crews were polite, personable and efficient. The only slight disappointment was the food. Apart from the content, having everything served at once uncovered meant that the main course was no longer hot when eaten. 1st world problems - eh?