vw t4 2.5 tdi?

on my 00 reg vw t4 2.5 tdi the water pump seized resulting in the cam belt breaking which in turn caused the cam shaft to break in 3 places, on dismantling a visual on it doesnt show any apparent damage to pistons or valves. is there a way to check the valves other than removal to see if all are seating correctly . being a flat head i couldnt see any easy way of checking so wondering if any of you have any tips on how to check, thanks in advance.