I'm not so sure that was the case. See following:
Journal of the Royal United Service Institution
Volume 57, Issue 1 – March 1913
Pg 413
TYPES OF CRUISERS – It has been decided to discontinue the use of the terms “armoured cruiser”, “protected cruiser, first class”, “protected cruiser, second class”, “protected cruiser, third class”, “unarmoured cruiser”, and “scout”. In future cruisers will be officially divided into three classes, namely “battle-cruisers”, “cruisers”, and “light cruisers”.
The term battle-cruiser will continue to be used as at present.
The term cruiser will be used to designate all vessels at present classified as armoured cruisers, and protected cruisers first class.
The term light cruiser will be used to designate the remaining cruisers and the vessels hitherto classified as “scouts”.
..... which suggests that the term "battle-cruiser", upon however technically informal a basis, was in use prior to the Admiralty's cruiser re-classification order.
Go here - https://usir.salford.ac.uk/id/eprint/29 ... 4-1909.pdf - for a good discussion of the early history of the term.
B