No power after replacing bevel

Hi iFixit, I recently changed the screen on my S4. Before adding the old bevel I put the battery and sim card in the phone to check the screen worked - everything worked perfectly. I then removed battery and replaced the bevel and then put battery back in - this time no power.

I thought this might be a case of the bevel pushing against the power button so I removed the power button from the bevel so I had direct access to the internal switch - again nothing.

Now lost for ideas - any help greatly appreciated.

Thanks,

JP