Screwfix Floor Filler (Tan)

Has anyone successfully used this to fill gaps in an old floor?
Did you sand then apply filler, followed by varnsish? Does the varnish take to the filler at all?
How did it look? Better than long gaps?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.