Royal artillery & St Francis barracks | Gwulo: Old Hong Kong

Royal artillery & St Francis barracks

I am looking for information on the Royal artillery in Hong Kong in the 1860s and 1870s please.  Haven't been able to find much online, or in libraries here in Australia.

my great great grandfather, George William Stainfield, enlisted in England in 1861 and was in Hong Kong with the Royal Artillery by 1868.  His address in that year was shown as St Francis Barracks.  My searches for St Francis Barracks keep taking me to the world heritage site in Macao - is that correct?  

I'd be thrilled to receive any information, or suggestions about sources please.

Thanks, Jenny