Huawei P10 rebooting and glitchy after screen repair

Hi, I replaced the screen on my Huawei P10 and when I boot up to the lockscreen and enter my pin the screen goes black and it reboots to the HUAWEI logo. Very rarely I will get past the lock screen and will be able to use the phone perfectly for a while but will get a sudden reboot. A couple of observations: When I do get it working and the screen is asleep, pressing the power button will not always wake it up. It wakes but the screen stays black and I have to hold down the power button to reboot again. The proximity sensor is not working when I am on calls - the screen stays lit up when I have the phone close to my face. I dissassembled the phone many times, checked all connections and removed and reinserted the proximity sensor. Still no joy! Just wondering if anyone can offer advice from experience. Best wishes