Having discovered Free-moN and perusing the standards, it looks like it's what I have been looking for.
Even if there is no one around to link with, it's definitely got appeal to work with solo, as modules can be easily taken down to work with on a bench.
I can change a module out rather than scrap an entire layout, there is no need to commit to a monolithic build.
I have been holding off buying materials until sure of a construction method, foam is something I can actually get!
I may be able to get the end plates accurately laser cut at a benchwork service, leaving me free to 'fill the rest in'.
Perhaps you could post some shots of your modules, how they go together, how they are built and in particular the details of the end plates?