There are many definitions and varying degrees of scale.

In simple terms (I like things simple), scale is about making a model that mimics a 'real' (full scale) aircraft. For example, 1/4 scale means the model is literally 4 times smaller than the real one being copied.

I don't believe there is a real Telemaster so, it's hard to determine what 'scale' it is. You might argue that a 1/5 scale pilot looks to be the right size for the cockpit so your senior telemaster is 1/5 scale.