Help with identifying inherited engine please

Hello all, what a lovely site! I’ve inherited my late father’s collection of model engines and am trying to make sense of them.
Here is one that he paid a lot of money for and I’d love to know more about it. Thanks so much...

It looks to be a ELF 4 cylinder. These engines were essentially all individually made in small quantities. They were produced in the mid 40's and the glow plug was introduced in 1948 practically placing most spark ignition engines into a cabinet or on shelves. Some of the ELF engines were made into glow versions as well. These engines tend to command a higher dollar value than most spark ignition engines. Spark ignition engines had quite a following a few years ago. It all depends on models obviously, as some are quite common and some like yours were not so common. I generally see more ELF twins than the 4 cylinder variants. Unfortunately, the close followers to most of these style engines are deceased or are up in age. We tend to lose the knowledge associated in using these. Many in my club still use spark ignition engines and do so with very good reliability due to modern battery sources for the ignition coil.