John Bowbrick served initially with the Hampshire regiment - Private No. 35160. He was either wounded or became ill and when he was sufficiently recovered he was transferred to the Labour Corps - Private, No. 106259.
He was entitled to the Victory Medal and the British war Medal, both of them have Labour Corps references.
He has no date of entry into a theatre of war on his medal card - so he would not have gone overseas before the beginning of 1916.
Charles Bowbrick, Private 1599, East Surrey Regiment. He went to France on 31st August 1915. He was entitled to the 1915 Star, Victory and British War medals. He was demobbed to the Class Z Reserves on 21st March 1919.
Sidney Bowbrick Private 3/5518 Duke of Cornwall's Light Infantry - entered France on 10th December 1914 - he had been in the Special Reserve before the outbreak of the war. He should have been entitled to the 1914 Star, Victory and British War Medals, but, according to the entry on his medal card, he deserted from the army and forfeited his medals.
Didn't find anything on the other two,
jds1949