It was a proprietary product from a local UK supplier who specialises in Tesla exterior/interior finish protection, so not something you could buy over there. But it looks like a typical leather/faux leather protection cream.
It is working very well, except for the huge mistake I made in using a black seat protector under a child seat, which has now transferred some grey dye from its backing foam onto the seat. Nothing I've tried will remove it so I'm now going to have to get it professionally restored when the child seat is eventually removed. The other seats which have just been sat on normally are all still perfect after 5K miles. No blue stains from jeans or any other staining of any kind. Absolutely no crease marks in the faux leather either or sagging of the material. It seems better than real leather in this respect. White is great for reflecting the sun too, no more roasted butt with typical black leather seats!
Would I choose white seats again? Probably yes, but the seat protector issue has certainly put me off. But I've learnt that lesson now, so as long as there are no other incidents I will be happy. For me it has to hold up well for 4 years only. If I was buying a car to keep for 10 years, white would not be my choice!