http://newmodeus.com/shop/index.php?main_page=product_info&cPath=2_27&products_id=219
Don't know about UK shipping...
Yes, I have one in my MBP4,1 and I have had no issues with it. You have to remove the faceplate for it to fit, but since the MBP has felt over the CD slot, you will never see it.
Just look on the same site for one that is 9.5mm SATA-SATA, preferably with no faceplate, but you can remove the faceplate if it comes with one.
Question. What kind of connector does the optical/drive use? I am under the impression it was not Sata? I have the 2.6ghz 4,1 model. I am trying to add in a second drive in place of the optical. OWC said they did not have a solution.
Best,
D