Thanks for the comments, guys.
I've had V6s before, both were 3.2 Vectras. Having had my own Austerity Measures for the last five years, driving a 1.8 non-turbo Saab (yes, they really did do a petrol one without a turbo), I wanted to go back to a V6, and was initially looking at the Insignia 2.8T. However, I soon realised that to get one with low mileage and be around four years old, I was going to have to pay around £15K, whereas my budget was £12K.
So I broadened my search, keeping the V6 as a requirement, and spotted the IS250. The wife and I went to a local garage that had one in to see if we'd like it, and were impressed with what you get for your money.
So I looked further and found this one, and have been grinning ever since.
I would've liked a manual box, but as a bloke (and, therefore, genetically predisposed to be lazy), the auto is sweet enough.