Thanks Mick, thought I was on the right track
I will take this little item :- http://www.slime.com/shop/tire-sealant/ similar to the old foam filler , but much more " tyre fitter " friendly. I don't think we are going via the Telegraph track anyway, but may utilise the coast road from just north of Cooktown to Bathurst Bay , then turn west to link with the Development rd.
and yes Jim....... you are 100% correct and have great ....vision
LP