In this guide
4. Power of attorney
You need to have power of attorney over property and financial affairs to act for someone with us without them authorising you.
If you already hold power of attorney to act for someone, let us know by sending us a certified copy of the power of attorney by post to:
Welsh Revenue Authority
PO Box 108
Once we receive this, we will only communicate with you around this person’s tax issues. Contact us for help with this process.