That is a nice Christmas present to get Larry!!, i think the Katie is my favourite of Roundhouses's locos, a close second would be the Lady Anne. 
I agree the Katie is my favorite also ( I now have two) and the Lady Anne isn't far behind (my first engine was a Silver Lady). I was disappointed though that I couldn't get some additional lining on the engine. It was set up to be done by Geoff Munday at Lightlines but, sad to say, it turns out he has retired due to having a brain tumor removed that was caused by lung cancer. What a shame - he was easy to work with and did great work.