Ken,
Thank you for the response. I've had a look at FindMyPast as per your suggestion without result (
http://www.findmypast.co.uk/search/armed-forces/births area?)
Despite this the birth is on the IGI (Batch C75017-9).
Is it possible that he is not military? Or am I looking in the wrong area.
Thanks for your help. His father is one of my 'dead ends' so if I can find more of him, it would be great.
Cheers,
Michael
PS: Just found something. On an 1881 Census William Frederick's sister CLARA says her place of birth is East Indies (most other times it is recorded as Richmond Surrey). FindMyPast has a suitable entry -- Clara Browne born in 1869 in Trimulgherry -- the regiment is the Royal Artillery. Another lead.