A whopping month and a bit since any substantial stock came back into stores, Argos (UK) seems to have gotten a small scattering. 387-ish branches have the Grey in stock, whilst nearer 400 have the Neon.
Whilst the likes of Very.co.uk and Amazon.co.uk are currently accepting pre-orders for certain bundles, it doesn't look like Nintendo.co.uk will be restocking the Neon version any time soon. The Grey version, however, is due back in stock in a couple of weeks.
North America's not faring that much better as the only retailer with any stock levels is GameStop, and only for the Neon version bundles (costing about $469-$499), not for the Switch by itself.
If you're desperate for a Switch but missed the tide, don't forget to check at your local retailers for fun anyway. A couple of months ago I found a few Switch consoles sitting on a shelf in Sainsburys, so it's worth having a look.