The spring mechanism is built into the Ferco multipoint door lock. The handle set does not have a spring. If the handle is not springing back up then the solution is to replace the Ferco door lock. They are available online, here's a link to a company I found when searching on google:
https://www.upvc-hardware.co.uk/locks-gearing-163/multipoint-upvc-door-locks-184/ferco-upvc-door-locks-169/
Chris, August 2011
