I have just had two 24 x 16 acrylics done at the Lakside branch. Because I did not have the pictures with me when I picked them up, I did not notice that they were to dark.
This was one of them
http://www.talkphotography.co.uk/forums/showthread.php?t=191207&highlight=southend
On my monitor the sea is grey/blue, the land behind is slightly darker, the boats are black and the sky is graduated red at the bottom going to yellow nearer the top.
On the acrylic you have to look hard to see the difference between the sea, land and boats.
I am going to take them back and ask to look at the pictures on their monitor again. I would expect what I see on their monitor, is how they should look printed.
The girl in the shop did try and darken the picture, but immediately changed it back.
I will let you know how I get on, I might even get a chance to do this today.