The age at mariage is likely to be more reliable, because he gave the detail himself - age at death is how old the informant
thought he was...
If you don't have details of his WW1 medal entitlement, you can download the medal card for £3.50 at the National Archives site:
http://www.nationalarchives.gov.uk/ Medal card of Trott, Danvers HCorps: Oxfordshire and Buckinghamshire Light Infantry
Regiment No: 30381
Rank: Acting Serjeant
If his service record survived the bombing of WW2, it will be at Kew, but can only be consulted in person, not by mail. Some service records are now online at Ancestry
http://www.ancestry.co.uk/search/, but only a few so far.
At the moment, I can't see a Danvers TROTT on the 1901 census or Free BMD.
Rambler