The simple answer to that specific question is: ATC are bending the rules at GLA. In the UK, ATC is not permitted to offer visual approaches to IFR traffic. The pilot has to make a request.
As far as noise is concerned, don't fall into the trap of thinking that just because you're over a city that's where the noise issues are. At MAN, all of the "noise sensitive" areas are little villages out in the sticks of leafy Cheshire - nobody seems to give a monkey's about noise in Stockport. Hence on 06 we can achieve a much better departure rate than on 24.
At EDI, the same is true. The "noise sensitive" areas are mainly the wealthy areas around Crammond, which are pretty much where you would be turning final (with everything dangling) on a visual approach for 24. Hence the night-time visual approach ban.
I know a lot of this is frustrating for you (believe me, it is for us too) but you cannot say that these things are somehow within the gift of ATC to sort - because, quite simply, they are not.
I would like nothing better than to have the first two or three IFR arrivals in a sequence on visual approaches: it means I can forget about them (almost) and get on with something else. But the reality is that we are working within a framework of (sometimes perceived rather than real) concerns from local residents that BAA are trying - diplomatically, I think - to address.