Exactly. I've had multiple quotes on the go at the same time before; just make sure to use the correct barcode for the best price when/if you decide to go with them.
I've used Envirofone for about 7 or 8 years now. In my experience, they've never knocked down the value of a device based on its condition; granted they have never been terrible or smashed, but my iPhone 5 was reasonably used and marked around the band, but they gave me the full value.
Thanks. Ive just "sold" my 6 plus to them for £462 with the EXTRA5 code. If the new phones aren't that great, I'll just not complete the sale.