So far, my rendering times haven't been too bad, usually 50 seconds or under for a frame, but with the addition of this lamp, they have started to creep up, to a maximum so far of 1:37.

I have to be careful as I don't want this to take days and days to render, but hopefully if I can keep each frame around this level, it shouldn't take more than a day or so:

1m 38s = 100s (approx) per frame.

Therefore: 25fps x 100s = (2500s) 41.6minutes rendering per second of footage .

So a 30s animation = (1250m) 20.8hours to render.

Fingers crossed!