User friendly XML form submission alternative

Hi,

I am not a programmer (I mostly dabble in PowerShell and Perl) and I am definitely not an API developer (I just recently discovered the mysterious world of Postman), so please bear with me:

I recently joined a small company as their IT admin, and was surprised to find a an ugly and weather-beaten kiosk computer located in the corner of the office space. When I asked about this, I was explained that a business partner required this company to submit certain reports at a regular basis to said partner's XML based web-services system. There is no browser based web form submission alternative available, so someone had in the past advised them to purchase a license to ReadyAPI which provides a somewhat user friendly forms interface for these XML submissions.

Now, this 3 year ReadyAPI license is coming up for renewal and I find the license costs for such a powerful developer tool to be extremely overkill for this use case only. Additionally, I for one am very eager to get rid of that old Dell computer that sticks out like a sore thumb in an otherwise neat and organized office environment.

I know that the same submissions can be done using SoapUI, but the secretaries in the office balked at having to edit the XML content directly instead of just using their beloved forms. I toyed with the idea of just providing them with Excel templates and a VBScript that would do the submissions for them, challenge is that there are various web services from this partner needed - some come and some go, and the required parameters change frequently as well. 

 How would y'all approach this challenge? Is there an alternative that can provide a friendly form input interface for submitting to these services while still being mindful of the dynamic nature of the required input?