The intervention with your private life has to be in accordance with the law and in the interests of the legitimate objectives.
It also has to be necessary - this is where proportionality comes in. If it was possible to achieve the interference in a less intrusive way, e.g. by asking you, they should have done this.
Note that the only legitimate objectives set out in Article 8(2) for interfering with your right to privacy are:
·Acting in the interests of national security, public safety or the economic well-being of the country.
·Acting for the prevention of disorder or crime.
·Acting for the protection of health or morals.
·Acting for the protection of the rights and freedoms of others.
None of these apply