Dangerous
IANAL, but the company appears to have disregarded the Employment Act (2002) and this sort of action is liable to land them in all sorts of hot water. The company should have followed Statutory Disciplinary and Dismissal Procedures.
Whilst with less than 12 months continuous service she would not normally be able to bring an unfair dismissal case to the EAT there are certain "automatically unfair" dismissals. Also, if she were able to prove discrimination she would be exempt from the 12 month requirement.
I'm not making any comment as to whether she falls into either of those two categories, merely that if she did she would have a case.