Hi,
I've got a smoothing capacitor (C2) on the input to the Reg. I'm not sure if this is readlly required as a battery is really a large capacitor.
Does anyone think I need another capacitor on the output of the Reg?
If the battery is fairly close to the regulator (say less than 4"/10cm) you should be able to:
Loose C2 altogether.
Move C1 as close to the pins of the regulator as practically possible - 100nF to 220nF is a good range, but the 330nF will do.
C3 should be around 22µF (10µF will do if you get a wet tantalum) and preferably a low ESR cap if possible (or move up to 33µF or 47µF). This should be as close to the regulators pins as well.
The major idea of placing these two caps is to make sure the regulator doesn't oscillate (since that's a bad thing).
Make R1 around 330 Ohm or larger, it's just an indicator (no reason for a blue/white or whatever you went for, when a plain old green LED will be so much more intuitive to read).