Thanks, Greg. The update is that I got the press working, after a fashion, with the help of a guy at my local gun shop. I managed to load a couple of hundred rounds yesterday, with only a couple of primer issues (they went sideways, probably because there weren't enough primers behind them to push them onto the pin properly).
The cartridge sensor on the priming pin doesn't work, so I get a primer fed onto the pin whether there is a case coming through or not. That means I have to keep a pair of pliers handy to pick them up off the pin if I haven't put a case in the press for some reason. If anyone can tell me how to fix that problem, I'd be grateful but I can live with it.
My assessment of the Pro 1000 remains that it is a cheap piece of junk. But it can be made to work if you've got time to mess around with it. The next time I have major issues with this press, I will either get rid of it, or cease using it as a progressive press.
Rather than buying a whole new press, I would probably just get a hand-primer and use the Pro 1000 for decapping, sizing, throwing powder (maybe), seating and crimping. I can see that it would be a pain in the neck to put the cases through with the decapping/sizing die on the press, then hand prime them, then put them back on the press to throw powder, seat and crimp (with the decapping/sizing die removed). But probably less of a pain than dealing with the priming issues on the Pro 1000. Eventually, I'd spend the money on a Dillon 650.
Cheers