Windows - Windows job in St Johns Wood, North London

Job Description

I need to replace cords of 2 Big Sash Windows, replace 3 glass sheets altogether and replace 2 springs for both windows as well - they are part of the double glazing. Both are huge pieces of glass, and springs don't allow me to hold the window up anymore.

I leave on the 1st floor of a house, however I have been told one can do this job from inside the property requiring no ladder.