Doubt it, there's no limit on numbers in the EPDG as far as I'm aware. If you're good enough, you're in
In theoretical terms, yes. In practical terms, no. I don't know the exact structure of the Quins one, but the London Irish Developing Player Programme looks at a couple of hundred boys at U14-16, with around 10 automatically carried forward each year (the others are invited to trial again each time), and the list trims down quite sharply as they get into the Silver and Gold DPP (the equivalent of our EPDG)