This is a technical misunderstanding.
If something is debated in the parallel chamber, the Standing Order says that if, when the chairman puts the question, it is opposed, then it cannot be decided then and there and it stands over to the main chamber. However, there is in fact no provision for putting the question in the main chamber. It's not put automatically. It doesn't just appear on the Order Paper that you have to suddenly vote whether or not the House has considered the matter of organ donation. There would have been no further debate, and it would be a quite pointless vote. Nobody would know whether to vote yes or no. It would have no meaning—although we do have some of those votes sometimes. In this case, we've only ever had it once in 20 years, for a political reason, a bit of a stunt, and it wasn't popular. Members asked why we were voting on it.
It is simply a votable matter. It isn't debated in the parallel chamber. We only have these debates where the House has considered a particular matter.