Rule for Policies to Redirect a specific URL

Please try these irule. Hope it will work as per your requirement.

    when HTTP_REQUEST {
    if { [HTTP::host] equals "testredirection.com" } {
    HTTP::respond 301 Location "https://google.co.uk"
        }
  }

OR

when HTTP_REQUEST {
     switch -glob [HTTP::header "Referer"] {
    "https://testredirection.com/*" {
    HTTP::respond 301 Location "https://google.co.uk"
      }
        default {
  HTTP::redirect [HTTP::header "Referer"]
        }
     }
}