I understand you could measure from height of the cockpit window, but is there any official dimensions stated anywhere such as FCOM or FCTM documents?
For the A320, this can be found in the CCOM (Cabin Crew Operation Manual)...
So the A320 is a 5.5 meter (17.04 foot) knotted rope stored above the side cockpit windows. There are 2 ropes in the cockpit (one on each side).
I can't find the CCOM for the A330 but it should be a similar size.