> This assumes that the employee has been working for the company for more than 2 years. If it's less than that, they have no such protection and can be fired for any reason whatsoever.

There are some protections, but yes, they are much more limited (in particular, anything that would generally be classified as automatic unfair dismissal is still protected, for instance for whistleblowing, joining a trade union, firing someone for raising a health and safety concern or for going on maternity leave).

You will likely still want to capture and document the genuine reason under either performance, absence or conduct grounds in order to protect against any invalid claim that the dismissal was because of a protected reason if it was brought to tribunal (when in reality it wasn't).