@pfoapplicant agree with the above. I just wanted to add that there is no correct answer as to the word limit. For cover letters, your written ability is being taken into account (at least off face value) so if you manage to write a 1,000 words, and can realistically say the same thing with less words, I would trim it down and get to the point.1. When I applied for TS, I stuck to the one side of A4 rule, as like you, it's what I'd heard looks the best/is the most succinct. 2. It is meant to be anonymous, so I don't think you should include your address or even name or anything like that. That's what I did at least, happy to be told I was wrong !!
Personally, I ended on around 800 words. I don't think they're looking for those that meet the 800 mark, but more so, those that don't waffle about things. Equally, if you can't trim it down, then the limit is there for a reason and feel free to use it.