I might just add that your 'Ready for departure' call is meaningless to an A/G operator.
Refer CAP 413, section 5.4.3 for use of 'Ready for departure' at an A/G field.
It's not meaningless at all even if it is not manned, if I'm on final at an A/G field and someone else calls 'ready for departure' that indicates clearly to me they have finished their take-off/power checks and intend to line up if the approach is clear. I'll be watching them and hopefully they will have seen me. It's a bit late when they say 'lining up', but if in doubt after a 'ready for departure' one can repeat 'G-XX Final' to remind them you are there. (Surely these things happen to others don't they
?)
I occasionally get 'Ready for departure' calls. My reply is usually 'Roger'.
I might pass them the wind speed and direction. I might pass them traffic information if I think it affects them. I'll often see them sit for several minutes waiting for an instruction that they're never going to get.