William Cottrell was was born c1894 in Birkenhead. He was the son of Thomas Rupert Cottrell and Sarah Alice Cottrell (nee Roberts). His parents were married in a civil ceremony in Birkenhead in 1889 March quarter
1891 Census: 37 Rowland Street, Birkenhead - Parents only living here
1901 Census: 7 Coventry Street, Birkenhead - Parents with children Alice Ada and William
1911 Census: 39 Prior Street, Bootle - Parents with Ada, William, Thomas, Ernest, Henry and Edna  
William was a factory hand at the Match Works in 1911. 
Reports on his death appeared in the Bootle Times on the 3rd and 10th August 1917. His photo appeared in the 10th August report and is reproduced here with the kind permission of the Liverpool Daily Post & Echo.
   Pte. Wm. Cottrell, K.L.R., was instantaneously killed in the early morning of July 21st, whilst at work with a pioneer company. He was the eldest son of Mr. and Mrs. R. Cottrell, 39, Prior-road, Bootle, and before the war he was a clerk-collector on the Overhead Railway. He was 23 years of age and was educated at Gray-street School, Bootle, and St.Thomas's C.E. School, Seaforth. He had been three years out in France. Writing to the bereaved parents, Lieut. J. Whyte said "He was a good fellow, and will be sadly missed by us all here. On behalf of his officers and comrades, I beg to tender you our deepest sympathy in the great loss you have sustained."

Bootle Times 3rd August 1917

A memorial notice appeared in the Bootle Times on the 19th July 1918 to mark the first anniversary of his death
COTTERELL. - In loving memory of Private William Cotterell, K.L.R., who was killed in action in France, July 21st, 1917. - Remembered by his Mother and Father, Sisters and Brothers, and Brother-in-law in France. - 39, Prior-street, Bootle.
He sleeps beside his comrades,
   In a hallowed grave unknown,
But his name is written in letters of love
   On the hearts he felt at home.
He died a soldier, rue but brave,

   For Britain's cause his life he gave.