I hope this diagram helps explain the antecedent battalions of the QVR. Personally I find it hard trying to hold all the different permutations in mind.
I think the 11th (later 6th) Middlesex, St. George's Rifles are represented by the badge I drew. Also see the following site for a helmet plate and collar badge
Here (There also seems to be a somehow related, Australian 7th NSW Voluntary Infantry Regiment (St. George's Rifles) with similar choice of badge). The St George's element was, of course, retained in the centre of the QVR cap badge post-1908.
There was a great post by Sonofaqms here a few weeks ago where he kindly posted pictures of his
Bloomsbury Rifles acquisitions.
I hope my summary attached is accurate as I am not an expert. Corrections very welcome.
Cheers,
Chris