The iPad app is pretty crap. But I use it as a print copy isn't going to happen for me in Australia.
Conrad, just make sure you login when trying to open up the new edition. I had similar issues to you, and at one point ended up with double, concurrent subscriptions. I contacted them and that got sorted out. The iPad now mostly remembers my login so I seldom have problems now.
I don't mind the enlarging action on an iPad, and do like it on the iPad so I have something to read if waiting around for something away from boat or home ie away from laptop. I read a newspaper on the iPad every day, so am quite used to the technique. But I must try the pdf download, that might be easier.