I made a bit of progress by simply moving the API key within get_model() as suggested in this post. However, updating/amending my code snippet to ..
import inference
model = inference.get_model(model_id="yard-wildlife/1", api_key="my_api_key")
results = model.infer(image="my_test_image")
print(results[0])
.. to run inference on a test image unleashes a torrent of dependencies warnings (?) and no apparent inference (on an image that works fine when just using Roboflow browser).
So, one step forward, one step back ..
Larry