Thanks to @russ and @nsj. The Waterslide Guitars Instagram feed reveals that the pickups are Mojo pickups, handmade in the UK.
https://www.mojopickups.co.uk/product/dual-foil-humbucker-gold-foil/ and yes, they’re magnetic.
Must admit, now that I’ve found them, I’m quite taken with the Charlie Christian models.
https://www.mojopickups.co.uk/product-category/pickups/charlie-christian/