Please read the sentence that follows in the 'details' section. What construction mix do we have? "If it were me who had found that horrible thing in the swimming pool last year, I wouldn't have come back this year!" (This is a polite adaptation of a line from a sit-com) The 3rd conditional version would be: If it had been me..... , I wouldn't have come back. Or the more formal, Had it been me ... I wouldn't have come back. The more circuitous 2nd conditional start (If it WERE me...) seems a little superfluous, but I do say it this way myself, sometimes. I'm not sure that the 2nd conditional start is valid for something that actually happened in the past (or, did NOT happen). It's a hypothetical IF, but about a real event in the past. Thus normally the 3rd conditional would be appropriate. It's not the same as "If I were rich, I would buy a palace." This is truly hypothetical, with no particular time reference. "If it WERE me who HAD BEEN there....." to me seems at times grammatically incorrect, and at others perfectly ok! I would like some truly high-powered input on this.I also am not sure if the 'who had found that horrible thing in the swimming pool last year' is actually functioning as a defining clause. Yes, I suppose it is, but take it out and the sentence makes perfect sense, and the speaker and listener know exactly who they are talking about. To me it's got the structure of a non-defining clause (stick it between two commas and remove it if you like) but much of the function of a defining clause (even if it not actually needed - and therefore would not be defining). Thoughts please. I have a C2 student of true native-speaker level and we spend hours arguing the toss over matters such as this. Any input would be most welcome!