Thanks for the advice.
Since getting it, I've tried it out in the garden and it seems very stable and damps vibrations quite quickly.
I've had my scope blow over a few times with my old tripods so I'm hoping this will fix that. I ended up with a cracked scope body on one occasion so I suppose I'm a bit more concerned about getting a good tripod than the average birder.
As you say it will be great for overhead objects as it goes so high.
From the picture you can see why I need to retract the legs from fully extended.