With regard to the 'there is a risk, so I'm reducing your medication' problem, the GMC's draft Decision making and consent Supporting patient choices about health and care guidance says this:
To make choices and decisions, patients must be able to understand and retain the relevant information and use it to make a decision. This means they need clear,
accurate information about the harms and benefits of any proposed course of action.
This needs to be presented in a way they can understand and is meaningful to them in their individual circumstances, so they can use it to consider the options and come to a decision. (paragraph 20)
To me there are two significant points.
The first is that the information about risks (and benefits) has to be accurate. So just saying that there is a risk does not comply with the draft guidance.
The second is that the information about the risks (and benefits) has to be tailored to the individual patient's circumstances. To me, this means that the doctor shouldn't simply say that there is a risk. To whom? How does that risk apply to your own circumstances?
The GMC says that
(The doctor) should check that (the) patient understands the terms (s/he) uses, particularly when describing the seriousness, frequency and likelihood of a possible harm. (The Doctor) should invite questions and discussion about the information (s/he) shares.
To me, this means that the doctor should say 'there is a one in 1,000 patient hours risk of osteoporosis if you continue to take levothyroxine at your current dose'. not just 'that there is a risk'.
By only saying that there is a risk, the doctor is not complying with this draft guidance.