Thanks for that further explanation. It is interesting.
I think the OFT should be interested in what you tell us and I think you should put your complaint in writing to them. The case officer who deals with Platte Media is Des Fitzpatrick. I suggest you also cc your letter in to Mike Haley, OFT Head of Consumer Protection, who I've found helpful in the past.
They have also failed to make it clear consumers are entering into a contract, and failed to point out that pop ups will apply should become outstanding. I did a test and tried to apply to one of their sites, the terms and conditions page was blocked out by the administrater. They clearly beieve rules don't apply to them.
Emphasise that your encounter with Platte did not make it clear that it was a paying site and that you were not required to confirm that you had read their terms and conditions.
They have providing more pop-ups than that is said in the undertakings, three months ago a collegue of mine wipe out the entire hard drive of his laptop, 2 weeks later the pop-ups came back. He has since then bought a new computer. Whereas for me I wiped out my computer and have not received any popups.
They should be particularly interested in this point as it breaches the undertakings.
Let them know about your experiences with Platte/Oriel when you have complained to them.
If you haven't already done so, also write to your local MP. Send him/her a copy of your correspondence to the OFT.
Do this as a priority, then, if Oriel continue to pursue you, inform them of your actions. It might be worth suggesting that, in the circumstances, if they continue to pursue you, you will make a formal complaint against their activities as a debt collection agency.
Oh, and let us know how you get on!
Good luck! - FF