If I was working A/G and an aircraft called 'ready for departure', rather than say 'roger', I would say either "G-XX 2 aircraft reporting in the circuit'' or ''G-XX, no known traffic' and leave it at that. I wouldn't use 'roger' as it is just wasting time saying another word on what may be a busy frequency.
Well that is an interesting turn around Final 3 Greens from:
As an A/G licence holder, it is not so much that I do not care, as I am not allowed to do anything other than pass on certain information. As Flyingmac says 'ready for departure' has no meaning, as I cannot clear them to enter the runway or to take off - I guess I could respond 'I have a spaniel dog', but the authorities would not like that
It still rather misses the point that 'ready for departure' at an A/G field is not for the benefit of the A/G operator.