Uk has barely any stock, it's the worst it's been since shortly after launch. Normally Argos has loads of stores with stock but its really low. I can only assume Mario Kart has given the Switch a huge boost or Nintendo has slowed deliveries to the uk to prioritise the US or something. Still sounds like a lot of stock in many countries in Europe though.
http://www.stockinformer.co.uk/checker-nintendo-switch