CrossRoads:
How about WS2801 per strip, or one for every 3 strips?
http://www.adafruit.com/datasheets/WS2801.pdf
That is EXACTLY what I was looking for! 
Does 3 LEDs, and can drive a transistor, also available for £0.30 ea inc shipping
(http://www.ebay.co.uk/itm/30pcs-WS2801SO-WS2801-ORIGINAL-3-Channel-RGB-Constant-Current-PWM-LED-Driver-/261034394045#vi-content)
Your help is VERY much appreciated.