I found the answer, well ChapGPT did...
There is nothing wrong with Traefik or the docker-compose files....homeassistant needs to accept reverse proxy. So I added the following in the configuration.yaml in homeassistant:
http:
use_x_forwarded_for: true
trusted_proxies:
- 172.19.0.0/16 # Replace this with the IP range of your reverse proxy
Now I can access the web interface through the external route.
Many thanks to ChatGPT!!!!