Stop a leaking overflow pipe in toilet?

Due to repairs being done, the tiling in the bathroom have been removed as well as floor boards. The toilet is still raised up but has moved away from the wall slightly. The overflow pipe (i think, it's the one on the left hand side) has started leaking now, probably due to slight movement of the toilet. Please can you tell me how to stop this? Would something like this be suitable as a long term fix? - Evo Stik Plumber's Mait Quick Leak Repair Putty - http://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=9271758&fh_view_size=12&fh_eds=%3f&fh_location=%2f%2fcatalog01%2fen_GB%2fcategories%3C{9372015}%2fcategories%3C{9372046}%2fcategories%3C{9372180}%2fspecificationsProductType%3dplumbing_tools%2fspecificationsSpecificProductType%3drepairs&fh_refview=lister&isSearch=false