Generating asserted login id in Sandbox environment

We are building an App that will eventually be accessed form teh NHS App - so we have authentication using an asserted login id.

Onboarding to the app is taking longer than we hoped and we have a mock NHS App frontend that we use to test the authorisation journey - we had been copying and pasting an asserted login Id from the mock site but have been asked to connect to NHS login instead.

I can get all that working and get back access tokens - but what I would like to do is build an asserted login id so we can leave the App code as it is.

Is this possible - and, if it is, can anyone point me to documentation for how to do it.

I have tried the solution used for the Hello world app - it did not get me where I needed to be.

Hi Anna. Are you integrated with NHS login now?

And having done that I’m assuming you can trigger a flow where a user logs in, but what you’re trying to do is keep your auth flow as live like as possible?