i'm in the same boat kev, tried finding info on google n u tube but no success, my ladders came with no rubber block but been told on here thats its dangerous without, so got one on order. i use mine for terraced windows and love it as no 'face in glass, hand over head' maneuvers. however wouls also love some do's and don'ts from experienced a ladder users, for example the grooves on the block, are they for using on the outside of jome stones etc etc
cheers