Difficult for me to see how a verdict could be overturned on the basis of such an unverifiable allegation - no guilty verdict could stand.
I agree, but I think there will most likely be an appeal application, they've tried everything else.
They may feel there are multiple points the defense for an appeal - televised trial, televised trial causing witnesses to not testify, privileged information entering the public domain...etc. etc? However desperate this all sounds!
Add: It's a cliche but trials with wealthy families can sometimes go on for a long time, entitled enough to think lil 'Johny' can't be guilty and the system must be made to work for them