I've seen said badge with a Sphinx to the top of this badge, was this an award badge & if so for what & how many were issued & for how long?
It took me a while to figure this one out but I understand that is if for The Diploma in Nursing course which started in 1921 in conjunction with Leeds University.It appeared to also take nurses from other Hospitals,see here ;http://rcnarchive.rcn.org.uk/data/VOLUME074-1926/page161-volume74-july1926.pdf?_ga=1.165978617.694708715.1386527293
As you can see there were 3 nurses who passed the diploma in that course so it would suggest that numbers were small.On a scale of rarity I have seen 3 in 30 years!
Thanks for the information & link.