Audi A4 Electric Fault(s)

Hi. I hope any Audi owners could help me.

I own a 2012 Audi A4 diesel. On Xmas eve, I turned the car over, engine came on, electrics came on etc but 'parking brake malfunction' appeared on the dashboard computer along with other dashboard lights such as ESP, ABS, glow plug symbol and an exclamation mark. The electric handbrake wasn't releasing and steering seemed to be really stiff.
I turned the car off, disconnected the battery for a few hours, reconnected it and car started up as normal only with the engine light lighting up (as suspected after disconnecting the battery).

I was driving around as normal for a few days until 7 days later the exact same warning lights came up again only disconnecting and reconnecting the battery wasn't solving anything. So I've left the car for around 5 days and after getting someone to plug a diagnostic machine in, the car is working as normal with no codes showing up.

Has anyone had this issue? Google isn't really my friend with this one.

Cheers