Powershell – SharePoint 2013 – Add web part to page using Client Side Object Model

I'm using SharePoint 2013 (Office 365), and I'm writing scripts in PowerShell using the CSOM to deploy various bits to Office 365.

I'm trying to add a web part to a page using PowerShell + CSOM.

I have this process working for publishing pages – that works fine.

I'm trying to add web parts to non publishing pages, such as 'NewForm.aspx' within a list. I understand that we can't checkout / checkin these pages, and webparts are added through design mode – however I can't get my script to add a simple web part to these pages (Content Editor Web Part).

My code:

    $wpxml = '<?xml version="1.0" encoding="utf-8"?>
<WebPart xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/WebPart/v2">
  <Title>Form View JS</Title>
  <FrameType>None</FrameType>
  <Description>Allows authors to enter rich text content.</Description>
  <IsIncluded>true</IsIncluded>
  <ZoneID>Main</ZoneID>
  <PartOrder>0</PartOrder>
  <FrameState>Normal</FrameState>
  <Height />
  <Width />
  <AllowRemove>true</AllowRemove>
  <AllowZoneChange>true</AllowZoneChange>
  <AllowMinimize>true</AllowMinimize>
  <AllowConnect>true</AllowConnect>
  <AllowEdit>true</AllowEdit>
  <AllowHide>true</AllowHide>
  <IsVisible>true</IsVisible>
  <DetailLink />
  <HelpLink />
  <HelpMode>Modeless</HelpMode>
  <Dir>Default</Dir>
  <PartImageSmall />
  <MissingAssembly>Cannot import this Web Part.</MissingAssembly>
  <PartImageLarge>/_layouts/15/images/mscontl.gif</PartImageLarge>
  <IsIncludedFilter />
  <Assembly>Microsoft.SharePoint, Version=16.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c</Assembly>
  <TypeName>Microsoft.SharePoint.WebPartPages.ContentEditorWebPart</TypeName>
  <ContentLink xmlns="http://schemas.microsoft.com/WebPart/v2/ContentEditor">/sites/forms/Style Library/en-us/JS/mobileform.js</ContentLink>
  <Content xmlns="http://schemas.microsoft.com/WebPart/v2/ContentEditor" />
  <PartStorage xmlns="http://schemas.microsoft.com/WebPart/v2/ContentEditor" />
</WebPart>'


$serverRelativeUrl = '/sites/forms/Lists/abc/NewForm.aspx'
$file = $ctx.get_web().getFileByServerRelativeUrl($serverRelativeUrl)
$ctx.Load($file)
$ctx.ExecuteQuery()

#$file.CheckOut()
$ctx.ExecuteQuery()
$limitedWebPartManager = $file.getLimitedWebPartManager("User")
$wpd = $limitedWebPartManager.ImportWebPart($wpxml)
$limitedWebPartManager.AddWebPart($wpd.WebPart, "Main", "0")
#$file.CheckIn("Script web part added via PS", "MajorCheckIn")
$ctx.ExecuteQuery()

Any ideas?

Many thanks.