Brewed yesterday. Didn't boil down the kettle caramelization aliquot as much as I wanted to. Was doing it in a 9 gallon pot and was getting scared about it scorching when it got down really low. As a result I don't think the color came out as dark as the real thing. Probably didn't develop as much flavor either. I boiled a little over a gallon down to a little over a quart. I also used 15 lbs of maris otter and 3 oz. british roasted barley for a 5.5 gal. batch. I went with NB hops although reading the Traquair website, it says they use EKG for all their brews. Your version will be closer in that regard. It also says they use Munton's malt exclusively, and as far as I know, Munton's doesn't malt golden promise. So maybe the Munton's maris otter will work out. I was sure to get the Munton's roasted barley too since it is much darker (453+ L) than the american roasted barley (300 L). I pitched a big starter of wyeast 1728 and it was bubbling immediately. It's chugging along right now at 58 degrees. I'll let you know how it turns out in a couple months.
I'm too lazy and have too many beers going to keep updating this!