iona is also an international software solutions company with probably a very good turnover, you'll have to check figures, but if you don't want to risk the wrath of a DRS go £650 and see what their response is.
It's a four letter domain, anyone could want it, I'd never heard of the place iona and doubt very many others have. iona is also a band, an old people's care body... check results.
http://www.google.co.uk/search?hl=en&q=iona&btnG=Google+Search&meta=
A DRS is £700 odd quid, offer under if scared or if you're sure of yourself, tip it at £1500. It's not the worth to someone in iona, it's the wider need for that domain.
Archive.org shows it hasn't been used for a few years, the last by taynet in 1999.
The majority of overture searches, 1000 a month shows holiday searches but a few show the tech side.On .com they show basketball so the buyer could be some nine year old from England who loves a US team.
It all depends on your needs, your progression and what your next moves are. And who the buyer is, anonymous or known. Do they use hotmail or exisiting address, is the IP uk, Europe, America or elsewhere? do they use disclaimer notes in their email?
£14 or £650, your decision. if you want to move up from £14, tell them there's a barter process and you both carry on until you reach an amicable figure, that way you're assured of at least a couple of hundred.