Hello Neil,
The error shows that the engine is trying to evaluate the #grdChildItems#=id# expression which is not a correct one. If the #grdChildItems should be "an element with id grdChildItems" selector, then the first hash should be escaped as explained below:
- https://docs.telerik.com/kendo-ui/framework/templates/overview#hash-literals - If your template includes a literal # character, which is not part of a binding expression and is not a script code marker, then you must escape that character or it causes a template compilation error. For example, this can happen if a # is used inside a hyperlink URL or a CSS color value. Literal # in JavaScript strings are escaped via \\\\#, while literal # in external HTML script templates are escaped via \\#.
If the issue persists, please share a simple runnable project or a dojo example replicating the issue in an official support ticket. That would allow us to investigate locally your exact scenario and help you more efficiently.
Regards,
Peter Milchev
Progress Telerik