Widevine problems in Chrome and Firefox on Ubuntu 19.10

I am having problems streaming some TV sites (ITV Hub, BritBox) on Ubuntu 19.10 in Chrome. This is a recent problem that has only recently started, a few weeks ago there was no problem streaming these sites. I regularly update my system and if is therefore very likely that an update is responsible and I only noticed days or weeks later.

I have started to look at the possibility that Widevine DRM is resonsible after James Shade Ubuntu 19.10 some drm content not streaming noted that-.

The problem is the same in Firefox (72.0.1) and Chrome (79.0.3945.130) (with DRM enabled in both). I note that both ITVPlayer and BritBox are getting an error 400 from a call to itvpnp.live.ott.irdeto.com/Widevine/getlicense as the page loads (this returns with a successful 200 response in Windows). This was all working fine in December

I have looked at the folder /opt/google/chrome/WidevineCdm and found this manifest.json file.I notice that there is no Linux entry under "platforms-OS" surely there should be.

{
      "manifest_version": 2,
      "update_url": "https://clients2.google.com/service/update2/crx",
      "name": "WidevineCdm",
      "description": "Widevine Content Decryption Module",
      "version": "4.10.1610.0",
      "minimum_chrome_version": "68.0.3430.0",
      "x-cdm-module-versions": "4",
      "x-cdm-interface-versions": "10",
      "x-cdm-host-versions": "10",
      "x-cdm-codecs": "vp8,vp09,avc1,av01",
      "x-cdm-persistent-license-support": false,
      "x-cdm-supported-encryption-schemes": ["cenc","cbcs"],
      "icons": {
        "16": "imgs/icon-128x128.png",
        "128": "imgs/icon-128x128.png"
      },
      "platforms": [
        {
          "os": "win",
          "arch": "x86",
          "sub_package_path": "_platform_specific/win_x86/"
        },
        {
          "os": "win",
          "arch": "x64",
          "sub_package_path": "_platform_specific/win_x64/"
        },
        {
          "os": "mac",
          "arch": "x64",
          "sub_package_path": "_platform_specific/mac_x64/"
        }
      ]
    }

There is a file called "libwidevinecdm.so under /opt/google/chrome/WidevineCdm/_platform_specific/linux_x64 but I cannot read it.

I would really appreciate any help with this.