Still not much progress on the layout, however on a recent family holiday to Devon I managed to slip in a trip to Pecorama. If you are ever in the area it is well worth a visit, great for families of all ages as well as model railway enthusiasts. Needless to say I spent some time and money browsing the shop and I now have all the track I need (I had some point salvaged from a previous layout but not enough). I also bought some card kits from Metcalf Models I intend to use for the factory, and low-relief houses for the back of the layout.
As an aside, I noticed the other day my 10-month old boy was playing with a micro-model railway layout. Indeed, it is what is often called a "Pizza" layout, featuring a circular track plan. It came with his Fisher-Price Peekaboo block train. It features a tunnel and train with 2-2-0 loco and 2 wagons, it even has digital control - that's right, you put your finger in a hole in the top of the block and spin it round! Is this the smallest micro-layout?