Distortion when replaying recordings from Virgin Box

I would try a factory reset.

The factory reset has 2 options it's only a partial system reset and not a complete factory reset if you select the Keep recordings option.

These are the factory reset options.

Keep Recordings
Format Disk

If you choose the Keep Recordings option that means you won't lose your recordings and any planned recordings or series links you've set up, but you will have to sign into your apps such as iPlayer, Prime, Netflix and ITVX again, also Match frame rate and Standby power consumption will go back to their default settings if you have changed them.

If that doesn't work you might have a faulty box you can either call Virgin on 150 from a Virgin phone, mobile or landline, or 0345 454 1111 from any other phone to report a fault, or wait here for one of the forum team to pick this up which might be 2 to 3 day's.

When phoning choose the option to report a fault, then ignore all the options offered and hopefully you should then be placed into a queue to speak to someone.

Is it all random the channel the recordings were made on and the channel playing in the background. Have you also tried a different HDMI cable and connector on the TV just to rule out anything there.