Thanks for your comment Mike,
I did think about doing something like that. I tried: "HIGH, delay(), LOW, delay()" but it faded in and out slowly (phase issues). The diac is definitely the way forward.
It would definitely be better for it to fade in instead of suddenly turning on. It's actually not that pleasant being woken by a 60W bulb at 6am! (I haven't brought a 20W bulb yet)
I'll give it a go next time I buy some stuff online.
What type of capacitor would you recomend for the smoothing (I think that was your intention)?
Thanks for reading,
Chris