Advice please..Speedometer issues

[2018poloauto]

Evening All,
I had some electrical issues.following water damage. After fitting new battery.my mileage has gone nuts. Changed daily by thousands and now way higher than the car has done.
I've tried a few mileage correction companies. Most don't reply, but 2 have tried to reset based on my recent mot mileage, but they both said they can't get passed the security on it. I just want it right. Any ideas?

Infotainment unit also glitches now too, but guessing that's a straight swap needed.