Well actually it was my garden railway and I built the three 9F's featured in the movie. They were being run by their new owners The final shot shows one of the 9F's hauling 34 freight wagons, but had power to spare for more if we had got them!
I also made another movie earlier on the same day - this one features an Aster Hudson I have recently overhauled for a friend. It is running with seven MTH ribbed 70'passenger cars http://www.youtube.com/watch?v=jGQ0e1d9jN4
A new company in the UK has started making rolling stock http://www.g1m.co.uk/ some are in the video but most look like there scratch built.
notice on there web site they are also producing a lovely Standard 4MT 2-6-4 locomotive these have just started being produced and I have seen a few running they are sweet /DesktopModules/NTForums/themes/mls/emoticons/whistling.gif"
Generally freight stock is easier to find than passenger stock of in the UK. There are a number of kit maker like Tenmille who make excellent kits although in 10mm scale. http://www.tenmille.co.uk/
With careful selection the scale discrepancy is hardly noticeable.
I very much like the kits made by Northern Finescale (a Canadian manufacturer). Their 5 plank open coal wagon looks great behind the BR 9F and their kits are very easy to build. www.northernfinescale.ca
Most of the rolling stock shown in my video was scratch-built, in particular all the bogie freight wagons. We still have a fair number of people in the hobby over here who enjoy building from scratch and there are several suppliers of castings and parts suitable for this purpose. However there were also some kit-built items in the video too (brakevans) and some commercial RTR coal wagons.
As Andrew mentioned, Tenmille are a good source of varied goods wagon kits and of course Northern Finescale have an expanding and excellent range which are now available (in the UK at least) as kits or RTR.
Please contact me off-list if you would like any more info. I sometimes have stock of used wagons available.