Very unlikely it will need replacement I think. Mfrs reckon on capacity < 70% of original as being the threshold they'll replace it at. I believe it's 5 years unlimited miles, so unless you've done say 500k miles it should still be fine.
In USA there's a 2012 Volt Mk1 that done 450k miles and the battery in that's at 20% degradation, admittedly it's only been using the capacity range from 20% to 85% SOC, but it was 2012 tech and there's been a lot of development & more understanding of the chemical decay mechanisms since then, so 500kmiles should be manageable surely. Elon's been talking about 1 million mile batteries...
And if it's that degraded, it may be cheaper to get a new EV than to try to refurb it. There will still be a market for local-range-only EVs as 2nd cars, learners for the kids, ...
