Mackenzie and Moncur (Deceased).....

...no reason why this ironwork maker should remind me of Randall and Hopkirk (Deceased), but you just know that given the age of the ironwork, the company will be deceased.

A quick google on these chaps revealed they produced some pretty interesting stuff; the plant houses at Royal Botanic Gardens, Edinburgh, the swimming bath at Skibo Castle, Sutherland (think Guy and Maddie wedding venue) and the Palmhouse, Sefton Park, Liverpool.