OK I've answered my own question. I downloaded the plugin and after some dicking around got it to work and I like it.
So for those who may follow here's what I've done.
Obviously download the plugin as per instructions
In the editor press F6 and enter this
npp_save
cd $(CURRENT_DIRECTORY)
make
Into the text box. Note that I like to auto save before the compile (npp_save) and that it seems you have to do the CD so make executes in the correct folder. Also I often work on 2 projects at the same time but in different folders so this is important to me.
This seems to work well, I swap to a different source file in a different tab (and folder), hit CTRL-F6 and it picks up the local makefile. So far so good.
Now I'd like it to highlight the errors and make them clickable. I believe you do this in the "highlight" dialogue (SHFT-F6), I enter
%ABSFILE%:%LINE%: error:*
which is supposed to highlight errors and even make them clickable to go to the error line. So far I haven't got this to work.
Also the console takes up a lot of the editor window but you can just grab it and move out of the editor so it's a separate window, good if you have a large screen.
______
Rob