Hi there, just to clarify we are only a Q&A site so we do not ordinarily do case law research which can often take hours and would simply not be covered by the very low fees we charge. So you will have to work with what we know through experience and legal knowledge rather than get specific case law references, especially if we do not know them off the top of our heads.
In your scenario, you cannot just make a list of mitigating factors you may have heard elsewhere as each situation will be considered on its own facts. What you have done is indeed likely gross misconduct but you do have the right to raise whatever mitigating factors you believe are relevant and hope that the employer takes them into account.
I must warn you though that stress, boredom, etc will not always be taken as strong mitigating factors as the employer can always say that there are plenty of other things you could have done to deal with this rather than resorting to accessing porn in the workplace.
Therefore, I would be mindful to use your long service and (hopefully) clean disciplinary record as the strongest defences here, and then add the factors you mentioned in order to provide a better insight into your state of mind at the time and why you felt you had to access porn at work to deal with it. Also, be careful not to try and turn this around on the employer, where you blame them for this as they will unlikely be happy about it and it can just make things worse. So avoid telling them the way they treated you is the reason for your actions as that would likely result in dismissal. Instead, explain general stress, or stress for other specific reasons, was part of the cause and apologise, expressing remorse and ask for a second chance, highlighting your service and record with them.
Does this answer your query?