I want to position 2 hooks into an exterior rough cast wall to string a clothes line from. The only hooks I could find were swing hooks, (sort of figure of eight things) which will do fine, but they are very solid, (shaft is approximately 10mm diameter). Is it just a question of drilling this sioze hole and sticking them in? (They will be too broad for rawl plugs). I seem to remember Tommy on Groundforce putting some goo on a bolt he was putting into a wall, but I think this was waterproofing rather than adhesive. Any advice on ensuring hte things stay in the wall?