I've just checked the Frank Baillie book and then they had two breweries . the Tadcaster one and the Rochdale one called the "Rochdale & Manor Brewery" (which they closed in 1974). That would explain those Greater Manchester ones including the one I've been to in Stockport. Melbourns is still listed as an independent brewer with houses in the areas of Gainsborough, Lincoln, Boune, Stamford, Oakham and Corby.
I think I got my South Yorkshire notion from a quote by the brewery saying they were just a small brewery with tied houses in the mining areas of Yorkshire which I assumed meant South Yorkshire.
I do remember the Melbourns change as I went on a brewery trip to Ruddles and stopped at one of the Stamford pubs. I get the impression that Melbourn may have then still owned or even still do own the pubs but with Sam Smith supplying the beers. I really wonder if they actually own all those old pubs in London. If they do they must be worth millions.