Interesting nickname for this place, didn't know it was actually based out of London.

Yes, interesting. I know it's governed with military precision from London. I don't know a lot more about them only that they can play a jolly tune or two in the park. I believe that it was the Canadians who first coined the name 'Sally Ann' I have just copied this:-

The Army was founded in 1865 in London by one-time Methodist minister William Booth. Originally known as the North London Christian Mission, in 1878 Booth reorganized the mission, becoming its first General and introducing the military structure which has been retained to the present day.[4] The current General of the Army is Linda Bond.