I don't have any solid proof to this, only a hunch and strong suspicion.
Most of the Alpha Pharma gear I've seen has been good, as good as you can ask for it to be. I've known a lot of people who've used it and had no problems, only good results. Now I have heard of people complaining on message boards about some AP products, never heard of anyone in "real" life complain about it though and every time I've heard someone on a message board complain about it, it seems that it always comes from a different source than where other people are getting their AP products.
This tends to make me believe that someone out there is using the AP name for their product when it's not legitimate AP. There is no reason not to think this since this type of thing happens in the AAS world all the time...counterfeit product is the oldest trick in the book.
Legit, good AP is well known and well used. A lot of pro BB use AP and love it.