Thanks to Glen for an enjoyable game yesterday and for tips on a couple of good sources of GW and alternatives to GW products. Just placed an order for some Mournfang Cavalry through one of them, two complete units in fact, saving myself approx 45% off the New Zealand price in the process.
No time to post our battle report today - but I did find the following model very interesting, its from the Titan Forge range which Glen suggested. They're from Poland and available through Maelstrom Games in the UK.
Its called a Gator Cannon but honestly I think it would look awesome amongst an Ogre army, and would make a great centre piece. Think once I've got the main Ogre units painted and based I will definately buy one to use as my Ironblaster.