Public Embed URL Filter issues

Hi 

I have a basic report that uses just one table in the model called 'WIP' this feeds a table visual.

The only visible filter in the filter pane is called 'UPRN' this comes from the table called 'WIP'

I am sussesfully able to filter the UPL for this report by adding this at the end of the URL 
?filter=WIP/UPRN eq 191875

However I wish to publicly embed this report. I have used the Publish to Web (Public) 

and copied the URL when I past this in my browser it loses the filter I have applied.
How can I add the same filter to the Embed URL 
thanks

Richard