O2 unlock request

I'm currently on an o2 Simplicity contract (SIM only) and I've been with o2
(In its various guises) for 7-8 years. Currently using a SEK800i.

Six months ago I bought a SE K750i on ebay which I used on o2 Pay and Go
before transferring to a contract. I've no of its age but it was well used
and abused when I got it though it works perfectly. Its locked to o2 and I'd
like to get it unlocked as I want to use a Manx PAYG SIM in it while on the
IOM for a week. I've just contacted o2 via the customer services function on
the web site, supplied them the phones IMEI number and requested an unlock
code.

So will o2 supply this FOC and if so how do I enter an unlock code on a SE
K750i?

TIA

--
JC