The same problem as with all museums in the UK is the lack of space.
Most of the exhibits are right on top of each other leaving very little room for you to get the shots you need.
Hendon isn't as bad as Duxford for this, but some of the exhibits have poor lighting, such as the Battle of Britain hanger.
We've not been back to Hendon yet this year but have made two trips to Duxford and one to Old Warden. Saving pocket money for a trip to the big apple early next year so don't know if the boss will let us do any others this side of Christmas.
Would very much like to get back up to Newark and probably one or two of the other larger museums, just have to wait and see.