That would be Ahmed from June 2010:
viewtopic.php?f=7&t=20163&st=0&sk=t&sd=a&start=20Other notes about this list:
The infamous £2,500 offer on that configuration was made to Mark in June 2014. He did end up winning what would be a fair £15,000 on a 4 blues/£250k five box, but from a 3 box Deal.
Any true fan of this show should know who made the £9,900 No Deal and the result of it.
Both of the £20,000+ No Deals on that configuration were from extraordinary gameplay circumstances:
Scarlet from May 2009 turned down the £21,000 as she was able to play the final round one box at a time and the Banker likely promised a £36,000 offer if she found a blue (which she then wisely took despite further goading
).
Pommy from December 2009 mainly turned down her £20,000 offer because the Banker looked inside her box and convinced her that she had the £250k. Sadly it was a bluff and she crashed to a blue win.
The one thing I can't recall, though, is who was offered and no dealt £13,500 on a 4 blues/£250k 5 box.
EDIT: Now I remember, it was Adam from May 2012. He then got a £35,000 extra offer at 3 box which he sensibly dealt, regardless of what Mark inevitably had to say about it at the time.