Wow, I worked for James Howden back in the late eighties and spent quite a few weeks working on this beautiful m/c.
The drawbridge was an access platform for servicing the rotating blade tip , which acted as a power control device and an air brake.
This m/c was the largest turbine on the Uk mainland at the time and luckily for us engineers even had an internal lift!
All the British wind turbine manufactures gave up in the 90's due to lack of government support - unlike other countries.
Hence all the current turbines come from places like Denmark and Germany.
I still have vivid memories of being in the nacelle whilst m/c underwent emergency stop tests - basically big brake callipers grab a big steel disc and stop rotation in half a turn.
Well done guys