GE Capital cards interests were bought by Santander in early 2009, and they moved quickly to dump the 'non-performing' accounts. However, I'm sure Santander should have informed you that they now owned your account. Have you received a statement of account from anyone over the past year? It's now a legal requirement.
However, it's not just the CCA and the NoA they can fail on.
While such an odd NoA/notice of claim is, I'm sure, legitimate, it won't please a judge as there has been no letter before action, and no opportunity to negotiate before action was begun and costs incurred. Therefore a judge would be very unlikely to award costs if these facts were raised.
Next - Cohen always refer to Clause 7, and it seldom exists. It is a serious flaw in their PoC but again they will claim admin error. I'm guessing you have not had the T&Cs which supposedly formed part of this agreement? Can you post up anything you do have?
The numbers above in the application aren't the clauses - there should be linked T&Cs which should have been given to you at the time the agreement was signed. If not, they can forget clause 7 and the interest (Carey v HSBC 2009) - someone like pt2537 might even be able to argue that this buggers up the whole claim on the same grounds (though I don't know what the case is when the bare minimum requirements are in the agreement, as here; it may just mean they can't apply clause 7).
If you haven't received them, you need to demand the T&Cs urgently, along with the Default Notice supposedly issued by GE Capital. They have to produce it as they have referred to it in the PoC. There's every possibility it will be invalid, so we must see it.
You must also ask for proof of the assignment, ie. sight of the DEED of assignment. Their paperwork is usually OK, but you never know what you might find. And boy will it annoy them...