Bluetooth and servo not working on L298P motor shield

Hi all, I'm having an issue with my bluetooth module when using a servo on my motor shield.

I have an Arduino Uno with an L298P motor shield stacked on top. I have 2 12V DC motors connected, 4x 18650 3.7V 9800mAh Rechargeable Li-ion Batteries connected to the shield, 1 HC-05 bluetooth module hooked up to TX and RX running off 3.3V and a mini servo motor running off 5V.

I am using an android app to control everything and have it all working perfectly. The only issue is that when I command the servo to move, it moves a couple of clicks, then the bluetooth briefly loses power causing it to disconnect from the android.

Disconnecting the DC motors doesn't change the issue. Taking the shield off and directly plugging in the servo and bluetooth to the arduino makes it work perfectly. So there seems to be a conflict when powering the servo and bluetooth through the motor shield and I can't figure out why.

I hope i've explained my problem well enough, I've attached a photo of my setup. Any help would be greatly appreciated!