FWIW (For What It's Worth), you can put oil over latex, so you're OK there. The usual cause of your problem is moisture based on my experience. Other than that, I'll have to say that your 'designer paint' is bad. If you search this Forum's BBS, you'll see LOTS of people that had problems with this type of paint. Again, from my perspective, I don't see even the BEST of painters have the best of success with these types of paints. It's all in the mix. In short, you get what you pay for (and that's in the Name; NOT the material.)
In my opinion, open your Yellow Pages, look under PAINT - RETAIL and pick a store like Benjamine Moore, Pratt & Lambert, MAB, Finneran & Haley (my personal favorite), and have them mix something up for you. Heck, bring in a sample to see if they can match it.
Even if a company like, say, Benjamine Moore made Laura Ashley's paint, IF it was the same paint as their 'regular' paints, it wouldn't matter which one you bought, would it? Soooo, they have to be different by design! Maybe you can e-mai Laura Ashley at her WEB site to see what she says. I'd be curious as to who makes her paint too. If you can find out, plez e-mail me at the above address. Other than that, maybe someone else has something more useful to offer than bad news.