ask for more info (family ages and backgrounds) so we can -

prearrange groups

food was ~£6 per head (£110 total)

short (colour) printed tutorial was important so people can go at different speeds

need to rehearse construction of pi, explorer hat, screens to get the right order!

test all screen cables (one was defective)

touchscreens were fiddly, but good as they can disappear/incorporate into the mess (rather than monolithic black things)

croc clips were very important to avoid soldering

first aid kit needed

explorer hats good but needed periodic resets in some cases

the raspberry pi docs are riddled with minor errors (https://www.raspberrypi.org/documentation/usage/scratch/gpio/README.md)