Here's a model you could really play with. Fold down the massive rear ramp and attach the winch to stones or whatever was lying around the floor and attempt to wind it in. Slap up the ramp closed and set off. Unfortunately, there was nothing else available in the range with which to unload at your destination but if you'd chosen a car then it could be rolled or pushed off.
This would last through to 1963 when the Bedford TK style cab would replace it. The 1100 Bedford Carrimore Low Loader model did not have suspension and the only variations I am aware of are the yellow and red cab colours, mid or dark blue (both metallic) shades for the carrier section and late editions will have shaped wheels in place of the flat ones. QDT have an example with a red handle on the winch but I am not so sure that wasn't just a one-off oddity.
I wonder what colour cab it had. Either would seem appropriate. This is a new combination for me and I hope to have this particular one in a while. It looks like a late model
The other item released in April 1958 was the Corgi Service Ramp.
This is almost identical, apart from colour, to the Mettoys 'Castoys' service ramp produced in 1950 and is one of two models that were continued into the Corgi era. (The other was the Karrier Bantam truck). Now quite hard to find - indeed, I am looking for one myself at the time of writing - in fully functioning condition, this is a splendid piece of engineering that might have been a great addition to any garage display.
It even has holes so that you can fix it to a surface to prevent movement as you pull the lever to raise whatever you have driven on to the ramp.
To the best of my knowledge these Corgi ramps were always silver on a blue base.
Here is the best picture I can find of the original Mettoy product.