Finally found some decent-priced size 9/43 (UK) knee-high boots.
Got mine for £17 - gobsmackingly cheap so I hope they don't fall apart, they seem well made enough so here's hoping. https://www.shoezone.com/Products/Lille ... lack-18838 was the one I went for.
With the change I bought a pair of these https://www.shoezone.com/Products/Softl ... Shoe-12235 but for a specific reason - I'm off to a "skooldaze" party next week so it will do with the uniform, comfy and I shouldn't fall over my heels after a few!!