Just went on to Goldsmiths.co.uk and found 25% off a GWF-1000BS-1JF.
Priced at £412!
I've ordered it and they have subsequently taken it off their site. don't know if this means that they never had it, it was a pricing mistake, or they had 1 and I've got it! They don't seem to show stock levels, or say if it is instock or not.
They have misnamed another g-shock as a frogman, so probably not too organized at their end.
We shall wait and see.....