http://www.veteransagency.mod.uk/service_recs/service%20_recs_army.htm - after 1920 you will need to ask the MOD to release his records to you (presuming you can provide proof of death and proof of your connection to him - you may need to get the direct next of kin (one of his children?) to sign off on it.
If he married/had children while he was over there, remember that those records would not be on the main index but on overseas BMD indexes. (Also see
www.gro.gov.uk, freebmd and 1837online).
Incidentally, I see you've put a couple of basic messages and not gotten much response; you really do need to give at least full names, and preferably a better idea of dates and how people relate to each other. (Although generally it is best not to give information for people who are or may still be living - most people do this by not giving details on those born in the past 100 years)
The reason for this is, for example, that there are 217 people named Knight in Portsmouth in 1901, and that's just males aged 0-40. So when you leave messages like:
Searching for information For KNIGHT ,TOVEY & HADDIGAN from Portsea Portsmouth Hampshire
Then there is little anybody can do unless they happen to have those family names in their tree, and although you might run across a relative, the relative:nonrelative ratio is likely to be pretty low. Meanwhile there's lots of people with access to resources that might help, but they can't do anything with just surnames. You might want to try something of the sort:
Searching for information For John KNIGHT, b. about 1882 Portsea, m. Mary TOVEY, parents William KNIGHT and Elizabeth HADDIGAN.
You'll find lots of
genealogy addictspeople hunting up information for you that way!
