Rest Parsing JSON

Configuration
1

I have an Inverter that is exposed on my network via:

> http://[redacted]/solar_api/v1/GetInverterRealtimeData.cgi?Scope=System

Through a web browser this yields:

{
   "Body" : {
      "Data" : {
         "DAY_ENERGY" : {
            "Unit" : "Wh",
            "Values" : {
               "1" : 17000
            }
         },
         "PAC" : {
            "Unit" : "W",
            "Values" : {
               "1" : 3635
            }
         },
         "TOTAL_ENERGY" : {
            "Unit" : "Wh",
            "Values" : {
               "1" : 16092000
            }
         },
         "YEAR_ENERGY" : {
            "Unit" : "Wh",
            "Values" : {
               "1" : 3692000
            }
         }
      }
   },
   "Head" : {
      "RequestArguments" : {
         "Scope" : "System"
      },
      "Status" : {
         "Code" : 0,
         "Reason" : "",
         "UserMessage" : ""
      },
      "Timestamp" : "2017-09-06T12:46:07+10:00"
   }
}

I am trying to get this value:

 "PAC" : {
                "Unit" : "W",
                "Values" : {
                   "1" : 3635

Which is the Inverters current power output.

I have been trying with the rest sensor configured like this in my configuration.yaml:

# Rest
  - platform: rest
    name: Inverter
    resource: http://[redacted]/solar_api/v1/GetInverterRealtimeData.cgi?Scope=System
    method: GET
    payload: '{{ value_json["Body"]["Data"]["PAC"]["Values"]["1"] }}'

I thought that this would work, but when run I get this error:

<?xml version="1.0" encoding="iso-8859-1"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <title>400 - Bad Request</title> </head> <body> <h1>400 - Bad Request</h1> </body> </html>

Should I be using a different sensor to query the Inverter?

Any other ideas?

Regards