iPhone 5S - 'destroyed' motherboard, photo advice?

Hi all

Am posting this with a sinking feeling as I already know the answer, just seeking confirmation.

My 5S died last week, battery wouldn't charge and once it powered down nothing would get it going again. Diagnosed as a 'destroyed' motherboard and written off by two different phone shops (not an Apple Store) - I have a new phone now but had 1500 photos stored on the phone which I now can't access (family days out and stuff like that). I didn't have iCloud set up and like a plod hadn't saved them to the computer.

Are they completely and irretrievably lost is my question or is there ANYTHING I can do to get them back? And the second part of the question is if they ARE lost does that mean its safe to sell the phone as a bricked spares or repair without the risk of someone else being able to access my stuff?

Thanks in advance (and yes, I've truly learned a hard lesson about backing up!).