.....Hi Anj...just read your posting re grafitti....my company offers Grafitti Removal...we use either a steam cleaner, chemicals and steam cleaner or cold water with a very small amount of silica sand...one of these usually works wonders....
Petra is correct that sometimes it cannot be helped that with older bricks the faces do blow off them but with experience and the correct method, grafitti is a nuisance rather than a monster....once clean the area can be treated with a "sacrificial solution" which makes it very difficult for the vandals to ruin the area again.....
My company covers the whole of Greater Manchester including some of Cheshire and Lancashire....give me a shout if you need us....Have Fun....Locko