Hiya Dan,
I dont live in a terrace but I do live in a semi-detached. I too have worried about this problem as I have three greys. I think the best thing you can do is to speak to the neighbours and try and be on friendly terms with them, I also invite mine round for coffee and they love to sit and listen to the greys.
I cover the birds at a resonable hour and they dont make a noise until they are uncovered, on a weekend they get covered a little later and this gives us all extra sleep without the noise.
I did mention to my neighbours that if the noise did get too bad I would look into sound proofing the walls.
I know they can hear them as I was house sitting the other week and could hear them when I went round there.
I dont think your situation will be like mine though as you only have the one grey, one grey I dont think the noise will be bad at all! At the end of the day, as long as its not unsociable hours they cant really complain!
Caroline.