To come back to this, I am still a bit puzzled why the ATCO needs to drag out the landing clearance.
From above, I understand it's to prevent another aircraft transmitting. But I don't see why this is a problem?
Surely, if you say 'Speedbird 123, cleared to land on runway 24, surface wind is calm', that's sufficient?
Is it because the pilot must also read back the clearance before touch-down and you don't want anyone else getting in the way before he does so?
Equally, I guess savvy pilots must realise when an ATCO is dragging out a clearance and would avoid interrupting it accordingly?