Pic 1 - Scott? Registration AM = Wiltshire 1918/19.
Pic 2 - I concur with the dating above for WL 4139 = Oxford 1928.
Triumphs -
Pic 1 - 1931 500cc ohv Model CTT. JO = Oxford 1931.
Other pics - Registration JG 6554? = Canterbury 1936, although the bike is a 1932/33 500cc ohv Model CD, which was the sports version of the Model NT. It could well not have been sold until 1936 as these were inflationary times. The 1932 model had been increased to £50 due to inflation, but due to lack of sales of such a sporty model was down to £47 at the start of 1933. With more inflation this increased again to £48. Unsold Model NT machines were down to £34-10-0 in 1934 , so I imagine by 1936 the Agents would be virtually giving them away - especially when Edward Turner's Tigers appeared in April!
Peter C.