Thanks, Pete. As mine was just downloaded yesterday from the Nik website, I can only assume it is the latest version. I have a 15-day trial, but it has convinced me already that I can see myself using it a lot.
The good news is that I can get educational discount on the Complete Collection - "Contains the current shipping versions of Dfine, Viveza, Color Efex Pro, Silver Efex Pro, Sharpener Pro and HDR Efex Pro" for £280, and it all works with Elements, CS3 and Lightroom. I assume I would have to choose one of those, rather than have it operate on all three, but one would be enough. I'm beginning to connect with Elements, so I'll probably go for that option.
Of course, the whole Nik suite will take some getting used to, and I forsee myself getting lost for a while. Hopefully it will all be as intuitive as the Silver FX is.
Oddly, I've just had an email back from educandi.co.uk regarding pricing. The educational price is exactly the same as the current special offer (non-educational) price from Nik. I've been advised to opt for the non-educational price as "Nik do not allow upgrades from the educational". So it seems Nik have really dropped the price here, and it seems to be for the full, not Select versions...