This is a very early Mamod Steam Roller the SR. Compare it to the later SR1 and you will see several differences. Most noticable are the wheels, whereas the newer engine has a rimmed wheel with a hole in it, this one has a sort of beveled rim and tends to shine up better, suggesting that they are made from a different alloy. The whistle on this one is typical of most of the Mamod engines from the 1950s. The hub caps are push-on chrome dome shaped fittings as against the much firmer top-hat ones in the later model. What dates it most is the fact that it is screwed together rather than pop-riveted meaning that this was from one of the very first batches of SR models. Surprisingly there are 2 pop rivets holding the crank bracket to the firebox. Now I wonder if that is normal or were there ever any that used screws. Most people might say 'Who cares!' lol.
The full restoration description is Here