Main difference is the geo. Trucker top tube is a little bit shorter, lower BB, longer chainstays, longer headtube and a slightly shorter fork. There are a few extra details on the Trucker too, extra set of bottle bosses, pump peg, spare spoke holder.
Nice job on the mudguards.
I get on well with Marathon Supremes (touch wood) - not overly heavy and seem more than durable enough for London roads and a bit of mild off-road.
What are the differences between the Straggler and the Trucker, apart from the rear dropout design? Lighter tubing presumably?