Westmore was born on the Isle of Wight, off the southern coast of England. On 6 November 1899, he signed up for British Army service, requesting to be placed in the cavalry. He served with the 16th The Queen's Lancers in the Second Boer War. He was discharged from service on 22 April 1901, at the rank of Private, having been found medically unfit for further service. His character description at the time described him as "Very good, trustworthy and obliging man" and "a first rate hairdresser, has been in charge of the regimental shop". He had served in the army for one year and 168 days.