Thanks for the info. The prices I saw were from PJRC and also a UK supplier for the Teensy 2, however, appreciate may be cheaper elsewhere
The Teensy 3 that I can see is 48MHz (but appreciate faster would be available). Obviously, different chip so not "Arduino", but then again... if you are going up to that sort of price then for a few dollars more than the Teensy, you could get a MUCH higher spec Raspberry Pi with HDMI high definition output running Linux or RiscOS
...anyway... that's a different forum
Back to this... coding is going well (display is working, but the command processor part needs to handle the differences between the single/double width/height). Hope to have updated files online in a few days, but would also like to get the set/reset graphic command implemented at the same time.