thank you ,
sorted !
I had tried to customise the layout of the basic tools by dragging them to a new position ,
when going this I moved the line into another tool sub heading which is why it had disappeared.
discovered this after hours of trying to fix it .
next problem my perpendicular line prompt gone when I drag a line off a angle . was here earlier now vanished
have tried double clicking the snapping angle settings to see if its listed there but can't find it ???