I bought them in late 2011, though I'm not sure about the warranty. Make an offer; I'm not in a massive hurry, I can bring them back here at Christmas.
Yeah, I don't think I'll come even close to your asking price, so chances are you will either sell due to my bump or reuse them. Still, just thinking out loud here:
The B&Ws I can get locally for ~£500, and I see 2 ebay.co.uk auctions with bids, one for £52 currently (6d to go, but there's a dent) and one for £255 (3d to go, but stands are included). In the UK they seem to go for under £400 on the stores.
As for the Sonos amp, locally it goes for ~£425 and the cheapest I see it on ebay is £285 (3d to go, full warranty new in the box), cheapest buy now is £390, but that's a store selling brand new. I can get it on Amazon uk too, for £395 less VAT, so ~£330.
With all that, it would cost me £925 to buy in my corner shop, likely less than £750 in the UK. So my offer is £450 in BTC, shipped. If you can assert there is still some warranty left and I can verify I'll be able to use it here I may increase that value, but otherwise that's the very best offer I can make, considering the risks.