Hi Peter,
I take my CF RC8 out west (past Warwick) and find that it does due up quite easily - especially in winter and/or shooting near zenith.
For the secondary, Kendrick sells a secondary heater specifically for the GSO RC series:
http://www.kendrickastro.com/astro/RCoptics.html
For the primary, Kendrick also sells heater pads - but only for >= 12-inch RCs. I usually just tape a couple of large dew strips across the back of the RC8 and/or around the 3" focuser extension tubes.
This keeps the dew away in most reasonable temperatures (without a dew shield), but below -5 deg C and pointing at zenith I find that the primary still frosts over...
Dave