Help required configuring traffic mirroring

We are using Traefik v2 running in kubernetes in a shared namespace (called shared), with multiple namespaces for different projects/services. We are utilising the IngressRoute CRD along with middlewares.

We need to mirror (duplicate) all incoming traffic to a specific URL (blah.example.com/newservice) and forward it to 2 backend services in 2 different namespaces. Because they are separated between 2 namespaces, they are running as the same name, with the same port.

I've looked at the following link, but don't seem to understand it: Kubernetes IngressRoute | Traefik | v2.3

This is my config:

apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
  annotations:
    kubernetes.io/ingress.class: traefik
  name: shared-ingressroute
  namespace: shared
spec:
  entryPoints: []
  routes:
  - kind: Rule
    match: Host(`blah.example.com`) && PathPrefix(`/newservice/`)
    middlewares:
    - name: shared-middleware-testing-middleware
      namespace: shared
    priority: 0
    services:
    - kind: Service
      name: customer-mirror
      namespace: namespace1
      port: TraefikService


---
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: shared-middleware-testing-middleware
  namespace: shared
spec:
  stripPrefix:
    prefixes:
    - /newservice/

---
apiVersion: traefik.containo.us/v1alpha1
kind: TraefikService
metadata:
  name: customer-mirror
  namespace: namespace1

spec:
  mirroring:
    name: newservice
    port: 8011
    namespace: namespace1
    mirrors:
      - name: newservice
        port: 8011
        percent: 100
        namespace: namespace2

I keep getting a 404 error. Any ideas what I'm doing wrong?