I think I ought to qualify my "You've got loads" reference earlier and give it a little context.
It would have been about 1980 ish and in truth he probably had 5. Now these were the only copies I had ever seen - so when you see 4 or 5 copies, to my mind alarms ought to ring. Probably in quite an unfounded way. But Rob would have got them wholesale, so if some had sufficient copies to sell wholesale they must have had a few. I should add that I have never seen another for sale (in the flesh as it were, never bought off the internet, I always got mine from other collectors, dealers etc).
It does remind me though of my dealings with Spot from Goole in the mid 70's. He frequently had multiples (4-5) and I once saw someone try the "You've got loads, I'm not paying that much!" approach and his response, along the lines of "I've got 5, when they're gone, they're gone, so suit yourself" saw the chap put his hand in his pocket, albeit reluctantly.
Now at that time, 5 of something you have never seen an original of looks like a lot - but I bet everything there sold and is worth a lot more than a £5 now!
The point being there probably weren't that many in the grand scheme of things, but over 30 or 40 years our memory tells us there were indeed relatively speaking loads, but even 500 copies of a decent record will disappear into collection and its scarcity will be re asserted over time.