Alistair would like to play Minecraft with his friends. As this requires access to the morbid pit of despair and the dystopian nightmare that is the internet, this is slightly tricky to do in a safe and private manner.
Java should work out of the box. Bedrock has some parental control issues that you'll need to consider. As far as I'm aware, Bedrock has an "all or nothing" approach to online connectivity. In order to access this private server, the permission needs to be set to grant access to online services. This means that, in addition to this server, the child will see other servers that they can join. Personally, we wouldn't do this and fully understand if you feel the same.
Connect to minecraft.alistair.philjarvis.net
I can't help you set this up other than the instructions below. I can't help fix any problems. I am an idiot with a keyboard.
The server will operate a whitelist of people allowed to access it. To start with, the server will be open to everyone. I will manually add the children to the whitelist then turn that protection on afterwards. This means that only children / people who have accessed the server before will be able to access it. No random people.
Each child will be assigned a 15³ safe space where only they can build things, store things, and not be attacked by other players. This will hopefully help prevent fights.
Your child will see a visual effect for each of the assigned areas, along with a name when entering. They will have unique colours so they can identify their own space.
Chat logs are stored for 24 hours before being discarded. If any problems occur, contact me to retrieve them.
NB: previous statement regarding parental controls. Also, I don't have bedrock so no screenshots. Sorry.