What a small world it is (Hello thewinelake)!
And if when you start Googling a question what turns up is a post by the person that commented to you about the matter... then I guess you're not going to find an answer!
I have seven programmes for said ballet, two in languages without definite articles, three "The Sleeping Beauty", and two "Sleeping Beauty" (both companies from countries with no definite article touring the UK).
In the course of my travels on Google I was also delighted to discover that composer Erkki Melartin also wrote music for a ballet Prinsessa Ruusunen just a few years after the more famous version, and of course as he was Finnish that doesn't help either