Thanks a million for the reply and the link. I’ve been mainly using online tutorials to learn about AE so its handy to have a reference guide also.
I realised shortly after posting, that the footage was actually vertically stretched in the comp, and that this is due to only one field of the interlaced footage being shown. This is standard as far as I know, and is remedeed when rendered. My rendered footage however seems to show the same, vertically stretched display with visible banding. I’m certain I’ve got the right PAR and field order, but on further reading of the guide i’m sure something obvious will pop out at me!
Thanks again.