Served a Section 21 and Now the tenant is fabricating issues and reporting to the council

Possession - Section 8 and Section 21

Hi, we have served a section 21 on a tenant which then the tenant reported the property to the council who have now issued a "Matters Requiring Attention" letter. The tenant went direct to the council and did not notify the agent or landlord of any repairs (annoying). We believe the tenant has fabricated issues which the council have now picked up on and sent legal requirement letters to the landlord to ensure he is fixing the work. We believe the tenant has purposely broken pipes under the sink to cause a leak and now council telling landlord to fix it. The tenant also removed the bath panel upon visit from the council and now council telling the landlord to fix that under HHSRS. Please can someone advise where the landlord stands here, and some advice to prevent further issues if the landlord is going to conduct this work reluctantly?