Not true from my experience, as a former employee of this estate, my position was simply not advertised and I got an interview by invitation.I would suggest that this vacancy has already been ear marked for someone , exactly how it works am afraid .
If they have gone to the trouble of advertising it will be a fair and open recruitment process.
The biggest obstacle any applicant is against is themselves, have a positive outlook, believe in yourself and make sure you do some preparation if you do secure an interview.
Someone has to get the job and why shouldn’t it be you.
Good luck to any applicants, it is a fantastic opportunity.