How to daisy-chain from Sona > Pavlovia > Gorilla preserving Sona id

My study directs participants from Sona to Pavlovia for the experiment and then to Gorilla for surveys. In the onward URL field in the online tab of the settings in psychopy I have included the following [gorilla link]?external_id=participant but this just fills the Gorilla public id with the word ‘participant’ and not the Sona/Pavlovia participant id itself which is what I need for combining data. Does anyone know how I should change this so that the Sona id carries all the way through to Gorilla?

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Hi thanks so much for responding to my query
based on the advice for the other platforms, I changed to onward URL in Psychopy settings to [GorillaURL]?external_id=" + expInfo[‘participant’] but it still does not seem to work- the Gorilla PublicID is simply recorded as "expInfo[‘participant’] rather than the Sona/Pavlovia id number which I was hoping for - if you have any thoughts on why this is, I would be really grateful

Please show a screenshot. It should be $"[GorillaURL]?external_id=" + expInfo['participant']