Problem with {{PARTICLE_EVENT_VALUE}} data definition

Hope somebody can help. I’m completely new to this and have very little experience with JSON and programming in general. I am trying to set up a webhook to PUT data into a 3rd party Data Portal. It requires that the data be in a certain format. I have got the the webhook to work with the following JSON example, which updates the temperature data on the portal with a hard coded value of ‘14.66’
{
“docType”: “jts”,
“version”: “1.0”,
“header”: {
“columns”: {
“0”: {
“series”: “temp1”,
“name”: “Temperature”,
“dataType”: “NUMBER”,
“units”: “°C”
}
}
},
“data”: [
{
“ts”: “{{PARTICLE_PUBLISHED_AT}}”,
“f”: {
“0”: {
“v”: 14.66
}
}
}
]
}

Now, the value I actually want to send is {{PARTICLE_EVENT_VALUE}}.
If I replace the ‘14.66’ line with the following line,
“v”: "{{PARTICLE_EVENT_VALUE}}"
my data portal does not process the PUT request:

I have read the Particle Webhooks tutorial by Rickkas7, which was helpful and I understand that the issue is because {{PARTICLE_EVENT_VALUE}} is treated as a string. The tutorial says I can overcome this issue using a body definition, giving examples such as:
“body”:"{“a”:{{a}}}"

I am unsure how to implement this into the the JSON script shown above. Could anybody provide a practical example of how I can use a body definition in the code?
Many thanks

I have looked into this further and the particle.io docs provide practical examples how this would work using ‘body’ in the JSON script - see image below.
However, I have discovered that the ‘body’ definition cannot be used in the Particle Console Webhook Configuration. The Webhook has to be created and implemented using the Particle CLI. This is another learning curve and is not a basic exercise of downloading a simple executable into the windows environment,as there are other software packages required for the CLI to function. A bit of time and effort is required for a novice like myself. I switched my attention to my 3rd Party Data Portal and managed to configure the parser to accept the webhook HTTP PUT, complete with quotation marks. Issue closed.