From what I've found online, it seems impossible for me to hoard these and sell them on for a price lower than those easily available online without making a loss (delivery charges'd be a large proportion, despite only being one stamp each). Considering that and the effort and the tiny amounts of money we'd be dealing in... I think I'm resigning.
This site seems the best, and I just recommend that individuals use it for themselves (the only drawback being the minimum order number), or someone going to the upcoming London Meet orders a lot. I might still get some made. Apologies for the false hopes.