I found the link to buy the upgrade but it said US$83 = £ (Sterling) 103. That’s not right: current exchange is 0.84 = roughly £70.
having left the checkout page, for some reason I cannot now find the link to order the just upgrade: the only checkout I get is for the full license. It is not clear from the site where to order the upgrade from.
This is my dumb sunday I’m sure, but I’d appreciate some guidance.