I don't think you can go wrong with either, I suspect the CC2's may be a bit more comfortable/less noisy than the Pirelli's. We had ours done via Kwik Fit mobile and they were excellent to my surprise. BTW do you know what PSI your mum runs her tyres at? On our 2018 car, the sticker says both 32 (or 33?) and 38, with a manual symbol next to the lower number. All it says is 'comfort' but no actual detail. We find 38 really hard going with the R Line suspension.Cheers.
Managed to get CC2 @ £539 for 4 (~£135 per tyre) fitted at Costco which is relatively dirt cheap, so going to go for those. I can't find the pirelli's anywhere!