Dr Marten - their women's fashion range, Evans, Clarks, Fat Face. Also - Had some from Shoe Express, they fitted well roudn my calves but fell apart after a few weeks. But were only £20. But I do love my Duos (and am also on public sector salary!).
Andn keep an eye out for Duo sales too - I recently bought some brown, flat knee length ones from there reduced to £55. They're gorgeous (sorry). But also Evans (though I've had shoes from there before that have turned out not to be watertight).
Next's wide fitting boots have wide calves as well as wide feet - I have a pair which fit (snugly) and am about halfway through the Duo range of fittings (having measured my calves but never actually bought from Duo, sigh).