SD
From the reports that we have had on the forum, the telephone assessments are taking around 45-60 minutes.
I would suggest that you write up a bullet list of points that you want to cover and keep it next to the phone, it's also been suggested that you have a glass of water available.
They are going to be asking you questions about your conditions and how they limit your ability to complete the PIP activities.
You should certainly mention any issues that you are having due to the Coronavirus, especially if they are causing you additional problems with the activities but be aware they can only consider issues that have had an impact on your for the last three months and are likely to affect you for the next nine months,
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems