"I find it a bit irritating when I call a station and another aircraft calls up to say that the station is closed."
I dont agree.
It is your duty to call up in the first place. It is very helpful of another aircraft to report the frequency appears closed if they have already tried rather than leaving you wondering if you have the wrong frequency or the box has failed.
I also think Jez was absolutely correct. There can be nothing lost in the two pilots exchanging as much information as possible if that reduces the chances of a collision. I see nothing wrong for example in saying I am at 2500 on 1008 five miles to the west of XYZ routing north. If the other aircraft is in the same area he might well respond I will descend / ascend to x to maintain seperation. In that brief exchange the chance of a collision between those two aircraft has been avoided.
On a wider issue I find it strange how often you will hear a pilot report his position to an A/G for example with at 2,500, 1008 ten miles to run form the south. Another aircraft shortly after will report himself to be at a similiar altitude and it is quite obvious form the call both might conflict and yet neither responds with "in view of the other aircraft I will descend / ascend to x to maintain seperation. It just seems common sense never mind the courtesy.