Having taken a look on Amazon, I see they do a line of AmazonBasics Portable External Battery Chargers, which may well suit my needs.
Looking at the photos, I see they all show as being 5 volts (which I'm guessing is what's needed for the Pi?), and a range of amps (as shown below), but have no clue what that actually means.
Are any of these unsuitable for any reason? Cheers.
PS, for anyone that's interested, here's my rough idea for one of the awards:
The power usb connector would be built into his foot, with just the contact exposed for plugging into the pi (making it practically invisible), with the wires possibly fed into his back, or down into a stand on which he can sit (containing the battery).
The LEDs would be used to scroll a message across the screen (maybe the name of the award, along with the description, and name of the winner). I'm not too fussed about it being an open circuit board (it's for a tech community after all), but I should probably put some type of diffuser on it, to avoid going blind.