It wasn't until I was searching for pictures of these little things that I realised that some of them were still in commercial use well into the late 80s/early 90s, so almost anyone can justify buying one.
This picture is from 1989 although this one was still in use in the mid 90s!
Ruston Hornsby 48DS at Blackett Hutton & Co. Guisborough by Idle Drifter, on Flickr
This is from 1986.
EBR10-026 by Jamerail, on Flickr
Type 48DS (RH 417889/1958) at Dollands Moor Yard when under construction. 1989. by Adrian Nicholls, on Flickr