I first saw this deal on SD and a lot of folks have problems with it. I encountered the same issues and had to email "THQ E-Shop - UK support team" to get it through, but with unintended side-effects.
Here are some notes on my experience:
1. Unable to "Create New Account" @ UK THQ site
a. I tried the "Create new account" UI several times.
b. Each time, there is no on-screen message or feedback to tell you that your account creation process failed
c. You could infer that your account creation failed if you tried to login immediately after the account creation process and it would return a 'No user matches..." error pop-up.
2. Ambigous UI/workflow on the check-out page depending on which payment method you selected.
a. If you use cc as payment method, you're required to fill in the email fields for Payment Details - which is confusing since you're not able to complete the account creation portion in #1 above.
b. You'll likely get a "Temporary Failure" (or similar message) on the next screen as you try to complete the checkout process via cc payment.
c. If you use Paypal, you're not required to fill in email fields for Payment Details, but the Paypal cost is at £5.00 rather than the after-coupon £3.75. I cancelled the Paypal transaction at this point.
3. THQ E-shop Support
a. I ended up emailing "support.thq-eshop@gamesplanet.com" and it seemed they help complete my cc transaction, with some unintended side-effects
b. I received 3 email order confirmations for 2 separate Purchase Order #s, likely, from my repeated attempts at trying to complete checkout via cc and getting the "Temporary Failure" message.
c. The initial email order confirmation may not contain the CD key, but a subsequent email should have it.
d. Of my 2 orders that went through, one was at £5.00 (no coupon discount) while the other was at £3.75
4. metaboli Download/Steam
a. The email order confirmations should have both the CD key and links to download the metaboli.com download manager and install files.
b. There is a 6x download limit to prevent "fraud"
c. However, I activated the CD key successfully via Steam and am D/Ling it from Steam right now. It shows up as a retail copy.
5. Summary
a. It looks like you may need to contact the THQ e-shop support folks to get this deal since there are so many issues
b. Do not use Paypal as it may not account for the coupon discount
c. Do not attempt multiple cc transactions as all may go through once you get THQ e-shop folks to help process your order. Also, not all will be at the coupon-discounted price.
This is one of the most horrible online shopping design/implementation experience. With so much time spent trying to figure out how to get the deal through, I don't think I want to contact them anymore to refund the extra order (at the higher non-discounted price). I'll have to check my cc account later (or the next few days) to see how may transactions were posted by THQ e-shop. None of the transactions showed up yet when I checked it.
If you guys decide to try it, good luck!