If the sole does come off with impact adhesive then I'll use windscren bond to glue it back on, it pretty much means it will be on for ever, but I dont think the boots will see another sole in their life time!
I am going to use some of the meindl cream on them to give a bit life back into the dried out upper! I think it will change the colour a little but I am cutting about with biege boots with black soles so I reckon my street credit is pretty much burst lol