Thanks for the replies!
In regards to ventilation, anything would be better than my Soulo

. I have had many many nights in it, and love it to bits. But it's breath-ability is terrible. I often find it to be frustratingly damp on my interior tent; and if any wind blows the tent, it literally rains on me inside the tent. The Terra Nova SV seems to have an open vent at the foot end too, so maybe not so bad. Pitched without the fly sheet it could act like a pleasant wind tunnel on baking days.
One main draw for me when I got the Hilleberg, was the outer pitch first design. However, I think I'd prefer an inner pitch first tent for like, 90% of my walking. I've only ever packed the inside up on a few very wet occasions, but on those occasions... Well, see my comment on the ventilation. Is wet, yo.
I've been informed of somewhere I can go to have a squizz at Terra Nova stuff, while not the SV, it will give me a chance for a bo-peep at least