The most comfortable loco's i've ever driven, with a lovely plush, bouncy seat and everything within reach. Downsides were the poor sanding equipment, the pipes of which were so narrow they blocked easily so, unless the railhead was dry and free of grease, you could have serious problems getting going on even a slight gradient with a relatively light train. The dashboard fascia also had a tendency to fall out due to the retaining bolt and washers being too small and wearing the plastic, the stove also took several hours to heat up and boil a can of water.
All in all i preferred 56's despite the inferior comfort and user friendliness. I did have a soft spot for 58018 though. That was a real howler when at full throttle. IIRR the first batch of 58's had hydrostatic cooling fans, and the later one's had fans driven directly from the engine. I don't remember at what point the change was made though.
I remember one incident that had me rolling on the floor. Before i go into it i should explain that on a class 56, the compressor unloader valve made a short, sharp "Pfffft" noise, whereas on a 58 it was a loud "Whooooooooooosssssssshhhhhh" that anyone who has seen one running up close will be familiar with.
We had one turn at Toton where we used to load up the fly ash wagons in Ratcliffe, and then work the train on to Loughboro, where it would continue on to Fletton near Peterboro. This job was almost always worked by a 56. One afternoon it turned up with a 58 on the front. The loadie emerged in his freshly washed, immaculately pressed overalls and called us through the fly ash loading hopper, which was pure white after decades of accumulation of fly ash dust. As the loco got halfway through the hopper.... "WHOOOOOOOOOOOOOOSSSSSSSSSHHHHHHHH!" I looked back to see the hopper had disappeared in a cloud of dislodged fly ash, and emerging from the cloud was the, now ghostly white, figure of the loadie, covered head to toe in dust.
......Well I thought it was funny anyway...
