Hi @Sunil1,
A warm welcome to the Bunnings Workshop community and thank you for your question.
Unfortunately, it is incredibly difficult to match timber stains as they are relative to the timber that was used. The Bondall Cedar Monocel Stain And Varnish looks like it will be a good option, but if you keep the existing coating in place and simply apply this over it, it won't look great.
To get a really good finish, you're going to have to sand the door and frame to remove the old coating before applying the new one.
Use 80-grit sandpaper to remove the majority of the coating, then use 180-grit sandpaper to smooth and fully prepare the surface for coating.
Manually sanding everything is a viable option, but it will take some time. To speed things up, you can use a random orbital sander for the majority of the sanding and a detail sander for the more intricate bits.
Once sanded and prepared, assess the surface to see if anything requires filling. From the images you've provided, I don't see anything that would need it, but if there are cracks or holes, use the filler.
After this, tape everything off to prevent getting varnish where you don't want it and then apply 2-3 coats of the stain and varnish.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
