Ok do keep in mind that my experiences are not with isolates but with just farm kveik.
I think the best known "kveik" for this would be from a choice of 2. So in no particular order:-
Voss Gjernes at 25 deg c - I used this for a Vienna lager (like) brew recently. Ive done testing with this strain at this temp for other lager like styles before and it really is very convincing as a lager.
Here is Norway this is the kveik of choice used in this way for a lager like result. In fact it is used for a huge amount of styles and just always seems to fit with the change being temperature.
An isolate sold by Bootleg known as Oslo kveik. I am unsure if you can get it in the UK though...
https://bootlegbiology.com/product/oslo/
This is very lager like apparently. I have just got the original brewery mixed kveik that it came from which probably has 20+ strains in it...this isolate has one of these that is a mutated lager strain.
That is not to say the Saure at low temps would not work...It has a lager like quality to it already...so at lower temps you could see that it skips its fruity character.