Thanks for all the comments, they are much appreciated. Luckily I'm not too bad for flooding so no rush on the lifeboat
I have completed some simple 3D models for C class roof boxes. My first time really doing 3D anything, though the plan in work this year is to start using 3D modelling for civil projects. I am getting an initial test print done this week, and if I need to tweak the design - roof curvature, height, length etc I can do so. The longest part is 40 mm.
I have found many pictures of the C class, but only a few that show decent roof detail. I have been looking at the details on the Silverfox models for inspiration. Not sure what to expect really, here is the model: