As he probably remembers, I've been following Gav's Zip saga for what seems like months now and I really feel for him. I have almost exactly the same A1200 setup and yet I haven't had the slightest problem installing my Zip drive with a PowerFlyer.
The stuff about mountlists and device drivers has been mulled over and over and the poor guy's getting nowhere. I'm far from an expert in any of this stuff, so I just follow the instructions provided by Elbox. Maybe he's simply missed something out somewhere. I don't think he's actually got the manual (?)
I've also read quite a number of posts to Gav on this problem and some of them appear to be quite at odds with the info in the PF manual. Of course, there's probably more than one way to skin this cat, but all the conflicting views on the solution has bemused me, so I can't imagine how scatterbrained Gav must be!
Anyway, have we discussed the Startup Sequence? If so, maybe I missed it, but I think it might be useful if you (Gav) give us sight the S/S you're using.
Cheers,
JaX