Hi there,
This is Bogdan from Romania.
I'm a mechanical engineer - specialized in the industrial robotic field, 3D designer, industrial designer and, 3D modeler.
For some of my projects, I'm also doing the physical prototype too.
I'm doing product design, industrial design, reverse engineering, ideation, etc.
I have over 15 years of experience working on various systems/devices across multiple industries, from concept to launch.
1 - the best solution would be the real reverse engineering of the existing enclosure - meaning to have the enclosure, get the dimensions and features, and redesign it, same time keeping count of the requirements/modifications
2 - it would be also better to work with both models (the enclosure and the pcb) so will have the proper assembly in fewer steps
3 - 3d printing of the enclosure should be discussed separately as is not know at this stage how much material will need and/or printing time
4 - as you are in the UK and I'm in romania, it is quite easy to send over the real parts and will make the reverse engineering and redesigning :)
For any more questions, we could chat here, including the whole details of the project, final price, time frame, deliverables, etc, etc...
Regards
Bogdan