Cheers for everyone's help on this. I'm much clearer on the carb icing issue. Although I'm through the solo student - low hours ppl stage of carbheat every 10 seconds!
I guess the trick with airframe icing is to fly with a good difference between temp/dp and to stay clear of any moisture. I guess the effects of airframe icing are very noticable very quickly!?
anyway thanks again for the help.
K