Default KitKat Update - Sound Issues

Good Afternoon All,

I have a branded LG G2 on EE (New T-Mobile UK), and EE being EE took forever to release KitKat.
I finally got it a couple days ago and enjoyed the smoothness of the new OS.

Then i plugged the phone into my car system.
An awful hissing and buzzing sound coming from the left channel. I get the same when i use my Bose Handsfree.
The hissing is less with LG headphones that came with the phone.

Additional to this, the ringer is stupidly quite, i can barely hear it when its on full volume sitting less than a ft away on my desk and only one of the speakers on the bottom is working.

I spoke with LG and they told me that i need to do a knock on update, which is seperate to the OS update but EE havent released anything yet

Now general bit of advice required....

Do I...

1. Return the handset and request it to be repaired?

2. Root and upload a custom a rom with all the fixes?

Also has anyone found a solutio to the problems listed. if you did can you post the thread