From within the report you can access the field note of the workcenter of the routing with

• [[ (line2.workcenter_id and line2.workcenter_id.note) or '' ]]

So what you have missed is the connection through workcenter_id to access the fields of mrp_routing_workcenter.

That's exactly what I thought Andreas, however, when I put the following in

     <td>
        <para style="terp_default_Centre_8">[[ (line2.workcenter_id and line2.workcenter_id.note) or '' ]]</para>
      </td>
      <td>
        <para style="terp_default_Centre_8">[[ (line2.workcenter_id and line2.workcenter_id.name) or '' ]]</para>
      </td>

The first part, which should be my note field is blank and the second part is correctly filled in with the workcenter name.

It's a little confusing