Jelly Bean on the Galaxy Nexus - forcing an update?

I bought my Galaxy Nexus in New Zealand - via parallel importing. I believe it came from Russia, given my manual was in Russian(!). But it works perfectly and is genuine.

A colleague there bought one from the same source the next day, and his arrived a day after mine.

I then moved to Canada, and got a Rogers sim card. All good.

However, my ex-colleague got a 4.0.4 upgrade about 8 weeks before myself. I tried forcing an update, but no luck.

Then last week, I finally got 4.0.4, and about the same day, my old colleague emailed to say he got an OTA update to 4.1.

What gives? Is it a geo-fenced roll-out? How can I force an update? (I've gone to system updates to check for an update, but no luck). Or would I have to root and do it manually? I'd prefer not to if there's a simple way to force an update...

Baseband I9250XXLA2, Build IMM76K.I9250XWLD2