if working from the ground, a standard operators will do. however, and please read this carefully because they will not let you work if you don't get the correct one. if you work at ANY height above or below ground where there is a risk of falling, then you will require a working at heights one, these are more difficult and have a higher pass rate. some sites let you get away with an operators, BUT they MAY throw you off site with a 'red' card if they are part of the scheme. a red card is a total site ban with members of the scheme. best off getting the right one first time.
cheers