Ooops, noticed the requirement for a two birth tent and deleted my post. Here it is again for the sake of history, since I have been quoted.
As the proud owner of two old-style Argos pro-action tents, I would have to recommend them. That's if you can find one ebay. They normally retail for around 25 pounds. They have made something of a furor in the hiking community, even inspiring their own internet owners club. The new version looks something like
this, but costs a lot more. The old version looked the same but was green rather than orange. Avoid anything with the same name that looks different, there was a really poor quality tent made in the same name.