Many thanks to Sergey for his excellent guides to Galileo! A star you most definitely are!
For anyone embarking on the local build of Yocto, there are a couple of GOTCHA's in the build, seems that an old version of source for ELF is on the GIT repository, this will lead to build errors and requires edits to 2 of the source files replacing "%a" with "%m" in 2 places in the first failing file, and, once in the second failing file. I apologise for not recording the names, but, when it fails you will get all the information you need!
The other major fail is in the module GUILE, I tried to sort the local source but gave up and downloaded the latest source from repository and it all built in the end.
It is a long time since I messed about with these things, (1990's), I thought that modern CVS had cracked all of these issues many years ago! Nope! Seems that the GIGO and Linux are still very much alive!