From a solicitors website:
"The act must also be done with the knowledge and intent that the image is indecent or likely to be so, though this is interpreted broadly to include unintentional downloads if done with awareness of the potential content."
My reading of this is that the act of accidentally downloading something "indecent" whilst looking for images of whatever floats your boat will be more likely to be with "knowledge and intent" if your kink is school uniforms than SS uniforms, for example.
That aside, I'm not sure why the world knows what's allegedly been found on his laptop.