I noticed this one was an open auction starting at about £2.00.....Scarey! But i also think a high BIN price is also scarey for buyers! What do you think?
My own thoughts is to start it at a very reasoanble price (£29.95, perhaps) to encourage people to at least look. Plenty of mouth-watering piccies will persuade them well enough that this is genuine. Be very verbose with the text as well and make sure there's no doubting the validity and desirability of the item (you've probably seen my long-winded descriptions :lol:)
But even starting at 0.01p wouldn't be a problem as I know there are enough people who will pay big bucks for this - probably even more if it was the ruby intaglio.
I really don't think you'll have a problem getting a 3-figure sum, although you could set the BiN at a silly price just to see if anyone bites

£350, £400? You never know...
Another thought is to split the two items and sell them separately.
Finally, of all the Posy vases, this and the Ruby are the only ones I would always have on display with absolute pride. They really are the bees-knees
