Do children have basic rights to Wi-Fi, food, and a bed?
The relevant parts are:
Freedom of expression and getting information: You must be able to get and share information with others, as long as this does not damage others (article 13).
However, even in the UK, it is unlikely that Wi-Fi, the internet or a computer would be considered essential for this. If you can get a newspaper, reasonable access to a radio and have the ability to socialise then that would probably suffice.
Health: You must also be able to get clean water, nutritious food and live in a healthy environment.
Note that this does not require any specific foodstuffs or any drinks other than water.
Standard of living: You have the right to a standard of living that is necessary for your physical, mental, spiritual, moral and social development.
This would include somewhere to sleep; in the UK this would probably be a bed.