hi peter , and welcome to the forum, cwgc have him at 40, this was not unusual my own g-grandfather was 47 when he was k.i.a. check out ancestry for service and British Army WWI Pension Records, with as much info you can put in the search,
BOOTH, GEORGE HENRY
Initials: G H
Nationality: United Kingdom
Rank: Private
Regiment/Service: Manchester Regiment
Unit Text: 1st Bn.
Age: 40
Date of Death: 27/04/1915
Service No: 2657
Additional information: Son of Harry and Mary Booth; husband of Sarah Booth, of 69, Victoria St., Longsight, Manchester.
Casualty Type: Commonwealth War Dead
Grave/Memorial Reference: Addenda Panel 59.
Memorial: YPRES (MENIN GATE) MEMORIAL
http://www.themanchesters.org/1st%20batt.htm1915
In March orders were recieved for the attack on Neuve Chapelle, on the 10th March the battalion marched to the SE of Neuve Chapelle, on the next day they attacked but where unsuccesful. On the 12th they attacked the Bois de Biez and eventually reached the fornt line trenches but suffered bad casualties. The attack failed mainly due to other units being unable to reach their objectives.
In April the battalion was ordered up to the Ypres area again where the situation had become critical due to the german gas attack. There the battalion attacked over a distance of 1600 yards and suffered bad casualties from machine gun and shell fire. Here Corporal Issy Smith won a Victoria Cross, exposing himself to heavy fire to rescue wounded men. The battalion was specially mentioned by General Smith-Dorien for their 'great service' in the battle of second Ypres.