As usual Our Archivist KR has responded with this:

Hi OMB.

This is the team that beat Wigan 22 – 11 at central park on the 2nd May
1959 to reach the Championship final ,it was played in front of a huge crowd
23.254 mainly Wigan supporters.

Hunslet went through to play St Helens at Odsal
on the 16th May.

Your Archivist K.