How to use form.handle in Custom field.html
I have updated the plugin files to make this work as I needed it to.

In sproutforms/variables/SproutFormsVariables.php, I have updated the $bodyHtml variable at Line 57 to include handle =&gt; $formHandle

$bodyHtml = craft()-&gt;templates-&gt;render(
    'tab', array(
        'handle'               =&gt; $formHandle,
        'tabs'                 =&gt; $form-&gt;getFieldLayout()-&gt;getTabs(),
        'entry'                =&gt; $entry,
        'formFields'           =&gt; $fields,
        'thirdPartySubmission' =&gt; !!$form-&gt;submitAction,
        'displaySectionTitles' =&gt; $form-&gt;displaySectionTitles,
        'renderingOptions'     =&gt; $renderingOptions
    )
); 


This means in my Template Override in _forms/tabs.html I can pass the handle as a variable

{%- if formField -%}
    {% include "field" with {
        form:                 handle,
        field:                field,
        element:              entry,
        required:             required,
        formField:            formField,
        renderingOptions:     renderingOptions,
        thirdPartySubmission: thirdPartySubmission,
    } only %}
{%- endif %}  


I can then do as I required with not needing to specifically specify a form name in my submittedEntry variable

{% set ourForm = craft.sproutForms.form(form) %}
{% set submittedEntry = craft.sproutForms.getEntry(ourForm) %}




The use case for this update is if clients can add forms through the Matrix, you need to get form.handle in submittedEntry so that you can populate the form post using value="{{ attribute(submittedEntry, fieldName) }} if the form fails validation (so that the form doesn't return empty on validation failure).

In the documentation the submittedEntry value is always manually set, however in this example you need to be able to set submittedEntry dynamically so that you can use generic Template Overrides in _forms rather than having overrides per form in _forms/formHandle.