I bought a UNO R3 ATmega328P CH340G USB Driver Development Board

hi all,
problem solved. Found a more up to date driver through this forum and instructions here:

http://kiguino.moos.io/2014/12/31/how-to-use-arduino-nano-mini-pro-with-CH340G-on-mac-osx-yosemite.html

Now appears to be working.

Greg