Robbie - try doing a Google search for Jake Thackray (the correct spelling), not Thackrey - you might find more references.

To answer your question: the counting system is real enough. Jake wrote the song Old Molly Metcalfe which uses it. He used to introduce the song with a tale about a shepherdess who died out in the fields with her sheep (as told in the lyrics of the song), and (allegedly)claimed it was a true story. Later on he apparently admitted it wasn't true after all, and he'd made it up.

As mentioned higher up the thread, there are several variations of the counting system in different parts of the country. Jake's was based on the Swaledale version.

I don't personally have the evidence that you requested, i.e. to prove that JT was the original source of the counting system, but I'm sure such evidence exists - someone else may be able to tell you where (maybe a reference to a pre-1960s book would suffice?).