Sorry if this post is a bit obvious to some members but maybe it will help others in future.
Background: Yesterday I was having trouble aligning the finder scope on my Apollo 60/910. I just could not get the crosshairs over the target. Today, with fresh eyes, I looked at the set up. I noticed that even when the finder scope attachment screw to the shoe was tight, there was still a tiny amount of play between the holder and the shoe.
I stuck a small amount of aluminium tape at the end of the shoe's base to raise the hight of the end of the shoe's floor. There was no longer any play and sure enough now the crosshairs are lining up perfectly.
As an aside, I unscrewed the finder scope shoe and was surprised to see how white the original colour of the scope was - got cleaning it straight away!