Bluetooth and WiFi issues

Hi,

I have been having issues for a while with the WiFi and Bluetooth on my iPhone 6. I have previously posted regarding this but didn't receive much in response.

The issue is very low signal for WiFi (2G) and seemingly non-existent signal strength for Bluetooth. I have tried taking the phone to pieces and putting it back together thoroughly as suggested but this hasn't yielded any success.

I assume the next step is the replacement of some of the hardware. Could someone please explain the best part to replace first?

Thanks a lot!

Duncan