Have run a quick check on the Medal index cards for ww1,There were just 4 William Allen Listed.If you can find a Service Number.That Matches it would help
Mike
Medal card of Allen, William Allen C
Corps: Royal Army Medical Corps
Regiment No: 54488
Rank: Private...
1914-1920 WO 372/1
Medal card of Allen, William
Corps: Army Service Corps
Regiment No: M2/049181
Rank: Private
1914-1920 WO 372/24
Medal card of Allen, William
Corps: Royal Fusiliers
Regiment No: G/38167
Rank: Serjeant
1914-1920 WO 372/23
Medal card of Allen, William
Corps: Royal Field Artillery
Regiment No: 94092
Rank: Gunner
1914-1920 WO 372/23