Is this it Spanners?
http://i263.photobucket.com/albums/i...cs/Nickwax.jpg
I tried this on my new boots after the factory waterproofing had started to go, It did OK but round the 2-3 day mark the leather was getting wet in the wear areas.
Iv tried spray on stuff ,silicon I think(both the above in the aim of keeping the gortex stuff good) and it was brilliant as long as your boot didn't touch anything other than water. five minuets walking threw grass wiped it off.
After watching BaldBob put 3 large tubs of snow seal on each boot,in his undies and on his sandwiches I have figured bugger the gore tex if it even damages it at all and have gone back to Dubbin applied like wirehunt said pretty much.
If you make it soak in good and proper over a couple of days it lasts for ages.