I cannot understand why in the UK anyone needs to change tyres 'seasonally'. I appreciate our Scandinavian friends might feel it necessary.. but not in the UK.
I have driven all over the country, in all types of weather. We regularly take winter trips into the lake district, Peaks and Scotland. Very wet weather, through flood washed roads in valleys and occasional snow. The Blue earths have been great.. and as I said previously, I don't hang around but I do drive within the limits of the conditions. The new TOYO are rated a step higher regarding wet weather braking, so I am confident they too will suffice whatever the UK weather throws at them.
I did for a few years when I had a BMW 540i Touring. My job involved extensive flying and I was often travelling to Heathrow in the very early hours of the morning to catch flights. Running winter tyres gave the confidence to be able to get to the airport irrespective of what the weather threw at me, especially as it was often around zero or below on many 3am drives during the winters.
Would my summer tyres have done the job, probably most of the time, apart from getting off the drive should there have been ice or snow on my drive/road at that hour of the morning.
Now retired, I just stick with stock tyres, but i do consider a possible future change to all-seasons for my other car for the odd winter trip to Scotland to visit my daughter, but I still need to weigh up the small risk of bad weather for the 1 or 2 trips vs the reduced tyre performance during the remainder of the year.
The Jazz will remain on stock tyres, no complaints with the Yokohama's