I've got the latest version of Kies 18.104.22.16844_18, and have checked for updates.
I'm an UK O2 customer, but with a replacement handset that was provided by an insurance company rather than the original carrier supplied one.
Kies says the current firmware version as:
PDA:K14 / PHONE:KI1 / CSC:KE1 (MTL)
And says this is the latest firmware.
Which seems incorrect, as the phone is still on Gingerbread.
Any ideas on why the ICS update isn't available?