Observations can either be face-to-face, by Skype or video? You will need to discuss with your assessor, which is the best option for you. You need to consider issues such as access to resources, consent and any safe guarding when considering the best option for you. Observations can also be carried out by an expert witness. The expert will however be expected to be a qualified teacher.
Witnesses can also provide evidence of what they have observed you doing. Their testimony should however be a description of what they have seen. They should not assess or pass their opinion regarding your competency, as this is the job of your assessor.