I'm in a similar situation Scotspaul, only window I have available is NE facing, though I did get hold of a temporary greenhouse to go against the SW garage wall. I've had some of my plants out there for a month now, they took a hit from a few 5c nights but I trimmed a lot of growth away last week and they're all recovering now, some not so quickly but they're getting there.
I'd say move them on to deeper pots if you can, get the first set of leaves on the stem burried, and pinch the tops out when you feel the main stem is long enough for your growing space, or when it splits itself off into a fork.
Should have some fresh pics of mine up soon.