I just bought a 53 plate S60 2.0 T SE.

From what I've read on the web, the electronics seem to be a weak point and there are lots of goodies to go wrong, but seemingly the 2004-on cars are a lot better.

It's a nice enough place to do some miles, the stereo is great, and it drives pretty well. Your T5 will be even sharper.
On mine the only faults I've found are:
the fuel gauge is dead,
the heated mirrors don't heat,
the rear exhaust hanger rots but I got a replacement clamp-on one on ebay for £15,
the NS headlight wiper doesn't like being woken,
and the load-levelling thing on the same lamp is dead - may just be a fuse but haven't looked yet.

On price, I think you can afford to make a much lower offer. I got mine for £1k and the big tax disc and fuel costs will put lots of buyers off a T5.