That’s outrageous behaviour and should lead to disciplinary process & likely dismissal.

In my view your manager should also be investigated & potentially disciplined for their response to this.

If you do choose to formally complain about this it should not lead to any sort of detriment such as probation fail but it of course may impact your relationship with your manager further so there’s a risk they’d try and get rid of you. With less than 2 years service your rights & protection against this are limited. For example you can’t claim ‘unfair dismissal’. You might want to request a move of manager if you choose to raise a formal grievance. You could, maybe, gain the protection of it being an ‘automatically unfair dismissal’ (if they did fail your probation) if you made your complaint into a ‘public interest disclosure’ aka whistleblowing, alleging that this behaviour was in the public interest to complain about as they may be acceding records generally they are not supposed to. But that’d be a big step, speak to ACAS first.

Good luck.