nice, murray.
the main problem with this photo is the vertical streaking. i'm not sure where that came from, but you might want to check your scanner and make sure it didnt come from there.
like murray said, there's quite a bit of .jpg artifacts in this photo. you can try the .jpg artifact remvover, scan at a higher resolution or clone these out. i cloned. i didnt do the whole image, however. i mostly just did the faces and some of the clothing, mostly on the gentleman in the middle.
i started the image a full strength clarify to add back some defintion and contrast.
i also rotated the image 1/2 degree to the left.
i ran a digital camera noise removal (in
psp) at a medium setting. didnt want to blur with noise removal.
the rest is all clone and push to remove some of the streaking and artifacts.
i did add a mild sepia toning to end.
and like i said, i didnt finish this. i just did enough to show what could be done.