Hi fraser, just one more tip - if you have surfaces that are touching each other edge-to-edge then probably you want to use the Edit > Join tool to glue them together, rather than the Booleans.

The Booleans are more intended to be used when pieces need to be cut with one another and some kind of material being removed in order to combine the pieces.

If you don't expect for the pieces to be cut, then Join will probably be the better tool.

- Michael