Here's the link to the BV-4D on FairPrices' shop in Amazon, with the battery quoted at just over £20, with free delivery for most European destinations:
As I discussed in my editorial on how to buy replacement batteries, genuine cells can principally be discerned by the price at which they're sold - so £20 looks bang on the money for the real thing. Plus FairPrices's feedback on Amazon looks excellent.
Of course, to upgrade your Nokia N8 battery, you've also got the small matter of getting out your Torx T4 to slip the end cap off the phone first - it's easy, but don't blame me if you mess it up! Still, replacing a two year old 1200mAh cell which is now probably down nearer 800mAh, with a new 1320mAh cell will instantly give you around 60% more battery life, so well worth considering.
Comments welcome - have you found anywhere else offering the BV-4D yet?
PS. Eagle-eyed observers will note that the BV-4D is often quoted officially as having 1400mAh capacity, yet it's now being quoted at 1320mAh. My own BV-4D, in the 808, says on the label '1400mAh', yet, when I charge the battery and monitor its stats with PhoNetInfo, it gives '1320mAh' as its nominal capacity and charges to just under 1300mAh (after a few months of use).
Which leaves me mystified. My only theory is that the BV-4D was supposed to be rated at 1400mAh and so this is what got put on the printed labels and in the launch marketing, yet the factories couldn't deliver this in the finished cells very often, so it got downgraded to 1320mAh officially thereafter. What do you think?