I think this is already happening. I ordered my lux in march and was being quoted 470 for the year. I was doing comparison quotes to see how much they were to insure as I didnt want pay a fortune. The 470 was with my current company hastings. That made my mind up to go for a cupra as it wasnt that much more than my golf at the time.
My actual renewal time has now come and comparison site quotes are now nearly 700 and my renewal letter from hastings was 980!!. No details have changed, no accidents, change of address, absolutely nothing. 39 years old, full no protected no claims etc
Rang hastings and they went through it all again and said the cheapest they could do was 610. So something has happened this last few months with the cupra's.
For interest I ran a quote through for my old golf and that was cheaper than last year. So that went down for me, but the cupra went up since my March quote.