Ok - sent phone on Monday, no email until Friday to confirm it had been received. Original offer on email was £106 but phone had a few scratches and signs of wear and tear so thought I would get knocked down a little. First offer was £35 which was a joke and promptly refused, second £50 which again wasn’t fair in my opinion so refused and mentioned local store had offered £70 which they matched and I accepted. Payment was made within hours.
I think like most of these companies they will always chance a low offer to see if you will accept it, unlike other companies they will negotiate and i am reasonably satisfied with the outcome.