not bad manners just a tactical move
Is sacrificing Q for Q bad manners ?

It all depends on the position and your style. Generally, trading queens to get into a quick endgame ends in a draw and is generally not very exciting.
If you wish to learn and improve your chess, I suggest playing through the middlegames with the queens to better aware yourself about the tactics and positional theory.
Technically, it is O.K., however, since these games aren't actually rated/important, what do you have to lose?

It sounds like you weakened his attack by exchanging (not sacrificing) queens, so it wasn't OK by him, but you did better after, so I would say it was OK for you. Nothing unethical about that, just good, common sense chess.

reckon it depends on the situation,manners,its war, surely, but war,remember, all is fair ,in love and war

Not bad manner or illegal.
Taking the queens off the board increases the likihood of draws and decrease the chance one side will win. That is probably what your opponent is getting at.
Though at your level I don't think it matters that much as draws are rarer at lower levels, or at least that is my experience.
Trading Queens is a strategy used by some people because it eliminates the most powerful pieces from the board. It is good if you can use your other pieces to win, but when your Queen is your main weapon and you can't win without it, that is when people get a little angry. While playing people, I've found that more experienced players don't get angry and immediately take the trade. Lower level players tend to get angry and not know what to do, constantly trying to avoid it. It is fine to do.

If he was ahead in material he should be glad you removed the queens of the board. You want to keep queens when you are behind to have some attacking possibillities.
No bad manners, you can do anything you want within the rules to win or draw (when losing)

I was having a game and a nice friendly chat with someone in Canada, when I took his queen (sacrificing my Q in the process). He then made a comment that it was not OK to sacrifice my Q that way because the game loses its purpose.
Is he right? Is it bad manners to go Q for Q?
During the game noticed he was pretty clever with his Q so I needed to get rid of it should the opportunity present itself even if it cost me my Q. He was in front on time and points when I took took his Q - but the situation started to go my wqy once both Qs were absent.
In my defence I know that the Windows computer game doesn't hesitate to swap Q's.
Any thoughts?
Your opponent has something to learn about chess. You say he was up on material ? All other things being equal he should be the one inviting queen exchanges to get a winning endgame and deny you middlegame chances.
To say the game loses it's purpose is to misunderstand what chess is. It's about winning and not about winning in a way we want to win in. Though of course this doesn't stop all of us trying to impose what want with what is there to be achieved - often to the detriment of our game

@OP: In answer to the specific question you asked: no, trading Queens is not bad manners, under any circumstances whatsoever.
The "purpose" of the game is to achieve checkmate, which is still possible with the other pieces. The game does not lose its purpose just because the Queens are captured. The Queens are not the essence of the Game of Chess.
Exchanging Queens as you described is not termed a sacrifice, but instead just that: an "exchange," or "trade" (as johnyoudell and dashkee94 have already noted).

It most certainly is not bad manners.
The only bad manners there are by your opponent.
^This.

One guy called me brain dead when I swapped queens with him. Then I checkmated him with my bishops.
I tend to work from the hypothesis that at my level my opponents will over-rely on their queen, so swapping queens can work if I can get my other pieces into play.

One guy called me brain dead when I swapped queens with him. Then I checkmated him with my bishops.
I tend to work from the hypothesis that at my level my opponents will over-rely on their queen, so swapping queens can work if I can get my other pieces into play.
So your opponent got beat by someone who is brain dead. Who's the loser there?
I was having a game and a nice friendly chat with someone in Canada, when I took his queen (sacrificing my Q in the process). He then made a comment that it was not OK to sacrifice my Q that way because the game loses its purpose.
Is he right? Is it bad manners to go Q for Q?
During the game noticed he was pretty clever with his Q so I needed to get rid of it should the opportunity present itself even if it cost me my Q. He was in front on time and points when I took took his Q - but the situation started to go my wqy once both Qs were absent.
In my defence I know that the Windows computer game doesn't hesitate to swap Q's.
Any thoughts?