So I managed to solve the lighting issues in Unreal.
There are two types of lighting in UE, Static and Dynamic.
Static lighting produces very realistic results but the learning curve is high and way beyond my current level. Dynamic lighting, while not quite as good, is much simpler to use.
This 5 second render at 30fps 1920 1080 took all of 20 seconds to render the 150 PNG files needed. I then imported them into Davinci Resolve to render the actual movie. The movie render from opening the software, importing the files and exporting the video too about 5 minutes.
For reference, I am currently rendering the same scene in Blender on my (admittedly not as powerful) laptop and it has so far taken about 2 days…
Thanks to my UE Guru Matt for pointing me in the right direction (more accurately, telling me exactly how to fix the issue).