Ocelot swagger redirection issue - swagger

Question

I am trying to implement Ocelot/Swagger/MMLib and .net microservices on my Windows 2019 server.
Everything is working fine, I can call each of the microservices correctly through the API gateway using postman, but I would like to display the swagger documentation as the API is going to be used by a third party.
If I use the ip address/port number I get the correct page displayed, with my microservice definitions. However if I reroute this to a physical url (eg https://siteaddress.com/path/swagger.index.html) I get the main swagger document but a 'Failed to load API definition' error, followed by 'Fetch error undefined /swagger/docs/v1/test.
The network page of my browser inspection gives a 'Http Error 404.0 Not Found'. The requested url is 'https://siteaddress.com:443/swagger/docs/v1/test'.
My ocelot.json is:
{
"Routes": [
{
"DownstreamPathTemplate": "/api/v1/TestSvc/{everything}",
"DownstreamScheme": "http",
"DownstreamHostAndPorts": [
{
"Host": "test.api",
"Port": "80"
}
],
"UpstreamPathTemplate": "/api/v1/TestSvc/{everything}",
"UpstreamHttpMethod": [ "POST" ],
"SwaggerKey": "test"
}
...
],
"SwaggerEndPoints": [
{
"Key": "test",
"Config": [
{
"Name": "Test API",
"Version": "v1",
"Url": "http://test.api:80/swagger/v1/swagger.json"
}
]
}
...
]
}
I have tried changing paths in ocelot.json and startup.cs. I can see nothing in the MMLib documentation regarding this scenario, which is surely common in deploying these sites.
Suggestion on where to go next appreciated.
Page with ipaddress and port number
Page with physical address and error message