They may have passed a judgment in a specific case or two saying that a given agreement was invalid or unenforceable. For obvious public policy reasons, which you yourself earlier alluded to, they are quite clearly not going to deliver a judgment which states that all standard form loans created before April 2007 are void or unenforceable, if there are a significant amount of such loans such as would cause a complete **** up in the banking system (which one would expect there are).
By all means, take your bank to court if you think it's a good idea though!
Sounds to me like someone's thinking of launching a cheap, nasty, opportunistic legal product; that's all.