This is a new Royal Collection catalogue of George III's military maps and various other military documents from the 16th to the 18th century, free and searchable - some excellent stuff. Here is a Guardian story about it ... George III's vast collection of military maps goes online ... and this is a link to the website ... Introduction
George III's collection of military maps Maps, views and prints ranging from the disposition of Charles V's armies at Vienna in 1532 to the Battle of Waterloo (1815). Royal Collection Trust https://militarymaps.rct.uk Cheers Maureen