Your room is certainly on the large side, about 50% greater area than my parlour. From the reviews in What Hi-Fi and in Home Cinema Choice, both the two subwoofers that you prefer are really very good. I just don't know what is the maximum room size that they would be comfortable with. You'll see that I also own Tannoy TS12 subwoofers, which I do like, but I recognise their limitations and perhaps your room is simply a bit too big for the TS12? You won't thank me for this, but if you can get hold of a physical copy of the May 2012 issue of What Hi-Fi, on page 62 is a group test of six subwoofers, including the B&W PV1D, which they did like and in their opinion won the test. However, the Jamo D600 is also just within your budget and seems a very serious device, with a fast 15” driver. I can speak now from my own experience, and when I got my SVS PC-12 Plus subwoofer in March, I immediately noticed the increase in both power and depth in my power over the single Tannoy TS12 that it replaced. LSound in Norway were confident that the SVS would have more than enough power for my room, hence I feel that it would be fine for your, larger, room also. You can now get it (rather cheaper than I did!) from Frank Harvey Hi-Fi in Coventry. Lastly, you could consider buying two of the current top domestic Tannoy subwoofer, the TS2.12. Your Pioneer SC-LX85 has two subwoofer preout terminals. Certainly I can confirm that when I went from a single Tannoy TS12 subwoofer in the kitchen to using two, the all-round improvement was noticeable. Two of the new Tannoy TS2.12 subwoofers would still be within your budget and would fill your rather large room. Believe me, I'm only trying to help!