Hi Nat and Borate. Most helpful and I now have it cracked. The missing link was scaling the clips. After playing around I found a really simple way to lay out 4 clips on the screen. I didn't need to use the split screen at all. To lay it out with Tracks 1 and 2 on the top and tracks 3 and 4 below them I did this:
Track 1
Scale: Zoom X and Y: 50, Offset X: -50, Y: -50
Motion: Scale .50
Track 2
Scale: Zoom X and Y: 50, Offset X: 50, Y: -50
Motion: Scale .50
Track 3
Scale: Zoom X and Y: 50, Offset X: -50, Y: 50
Motion: Scale .50
Track 4
Scale: Zoom X and Y: 50, Offset X: 50, Y: 50
Motion: Scale .50
Works a real treat.
Thanks again.
Max