I don't believe step dancing had "long died out" by the time Meredith began collecting - it was more the case that their was no one collecting the dances. Shirley Andrews, the pioneer of dance collection in Australia, wasn't interested in step dances which she regarded as male-dominated. She greatly regretted this latter and was keen in supporting ongoing research.

In searching for more information about Frank Collins' tune, I have this response from Katie Howson, who plays for step dancing in England:
"First part – don't recognise it

Second part is related to Soldier's Joy and other well known variants used for stepping under many names

Third part is a floating stepdance /breakdown theme – see for example Sheringham Breakdown on Billy Bennington's 'Barford Angel' CD and I think also played by Billy Cooper.


My theory is that musicians who played for stepdancing often freewheeled a bit and put various 8 /16 bar phrases together. They usually played solo so there was no need to consider anyone except the dancer and their own tastes!"

Cheers,
Heather Clarke
http://www.colonialdance.com.au/trad-steps