A series of 3 pictures of a Sunderland launch from what I guess you are calling the South Slip, with the first pic identical to the Iris on the slip in front of the hangar.
In the aerial photograph the 2 slips can just be seen to the left of the picture.

I still say N.slip because of the hangar, both slips are fairly shallow (nature of the Med surely?). Both North and South slips had two actual slipways, they were just seperated sites, I think you can see both in that last pic.

Excellent pics either way.