Ok I am doubtful that this is a GDPR issue if there was no personal information recorded about you and it was just you talking on camera. The GDPR only protects personal data and if no personal data was recorded, then it is not a data protection issue.
As to the dismissal, if you have been continuously employed at you place of work for less than 2 years then your employment rights will unfortunately be somewhat limited. Most importantly, you will not be protected against unfair dismissal. This means that your employer can dismiss you for more or less any reason, and without following a fair procedure, as long as the decision is not based on a reason which makes a dismissal automatically unfair. These include:
· Discrimination due to a protected characteristic (i.e. because of gender, race, religion, age, disability, sexual orientation, etc.)
· Taking, or trying to take, leave for family reasons including pregnancy, maternity/paternity leave, parental leave, adoption leave or leave for dependants
However, if the dismissal had nothing to do with any of the above exceptions, you would not be able to challenge it. In that case your only protection would be if you were dismissed in breach of contract. That would usually happen if you were not paid any contractual notice period due to you (unless you were dismissed for gross misconduct, where no notice would be due). If you did not have a written contract in place you would be entitled to the minimum statutory notice period of 1 week. The employer would either have to allow you to work that notice period and pay you as normal, or they instead have to pay you in lieu of notice, where you are paid for the equivalent of the notice pay but your employment is terminated immediately.
Does this answer your query?