Row 18 is indeed configured 3-2 - it's because the aircraft tapers in quite substantially at the rear. I have sat there a couple of times, particularly for flights inbound to LCY where you can deplane from the rear door as well. As others have noted, the Avro is very tight in all rows; I make a point of avoiding it where possible. Row 18 is fine if both of you are small (hope this isn't getting too personal ) but be warned there is vv little elbow room, and the window seat is pressed right up against the cabin wall (with no armrest IIRC). Great if you want to snuggle up to your travelling companion (but avoid it if not), and as always it is preferable to the dreaded middle seat. If you can't get two aisles then go for it. One final piece of advice - do not be tempted by row 1 for any reason. The seats are far too close to the bulkhead and there is a shocking lack of legroom (I have made this mistake far too many times!)