This is a short history of Edith Lester's life from an interested party:

I'm not sure if you know what Edith's 1908 medal is for - if you do, forgive the following. The R.L.S.S. inaugurated a ladles' national life-saving championship in 1903. Club teams of 6 swimmers were timed for completing the same tests as other teams by a local A.S.A. official, in their local bath, and the times were then relayed to the 8.1.5.5. who gave medals to the fastest teams, once all the times had been received. The idea was to complete the tests on the same night, nationally. This was to overcome the expense of travelling 6-strong teams, chaperones, and officials to a specific venue. So, of course, until the results were made known, each dub was in the dark as to their position in the competition. Once a club had won the championship, that group of 6 girls/young women were barred from competing again, and a new sextet would have to be trained up and entered for the following year's competitor, so as to avoid one crack side dominating, and in order to promote and grow the practice of life-saving skills. The leading female swimmers in Britain took part at least once during the pre WWI years, and Edith Lister was one of the top Yorkshire sprinters. Her team completed (as did the others, of course) the following tests: 

2 x 108yds (any stroke); 2 x 72yds on the breast; 2 x 72yds on the back; 4 x 18yds with a 'drowning team member (each rescue via a different method). 

So you had to be profident in all aspects of life-saving, not just the fast swimming part. The championship seems to have been popular amongst the women, as al the leading clubs took part, and the entry was usually In double figures. It was certainly an elite-level event. 

Edith was born in Sheffield in 1892. A greengrocer's daughter (she is helping in the shop on the 1911 Census), she was runner-up in the Yorkshire Ladies' Championships of 1908-09-10-11. In 1911 she qualified as an A.S.A. coach, the top coaching qualification in swimming. She was the 337th person to pass the exam, which had been going for a little over 10yrs. She married in 1918 and had two children but died in Sheffield at the age of 31yo, 20 Mar 1923, presumably from childbirth complications, as her second child was born the same quarter she died.