Hi Dunelm,
Knew I was coming to Liverpool again this weekend to do more family research using Gores microfilm, so took your details to see I could help more.
Searched Gores 1923 to 1931 each year and found your William Henry Cowley, Postman at 58 Leven Street Kirkdale off Westminster Road ( My Mum was just staring school in 1930 at Westminster Rd School- small world eh)
On the 1930 Gores index William is shown still at 58 Leven St but NO Profession shown on Street Index listing or his Surname listing.
On 1931 Gores a Frank Spiers - a Ships Steward is shown at 58 Leven St and there is NO listing Alphabeticaly for William Henry COWLEY in Liverpool
only a William Cowley - Confectioner at 99 Peel Rd Bootle
so unless he changed profession - assume he emigrated 1930
as the 1930 & 1931 Death Indexes show on 1930 March quarter one W H Cowley aged 75 died in Nottingham and two William Cowley's both aged 46 dying in Liverpool one in June quarter one in Sept - none in 1931
Neighbour at No. 64 Duncan Metcalf - Marine Engineer shown living at No. 64- 1923 to 1931 inclusive.
Have taken screen prints on the indexes 1923 to 1931 if you want them scanned and emailed,
send me your details privately.
Hope this helps.