Hi, what you can do is contact this guy:
http://www.customgunandrifle.com/products/ground-alkenet-rootand buy the ground root. Then you can mix your own filler/stain using water, alcohol or spirts and a filling of your choice.
This gives you a true English red colour that was only available with the very expensive Pilikton stain which probably could not be shipped to as it was a flammable liquid.
A slurry of matching sawdust, alcohol based stain and clear shellac, rubbed in across the grain fills well. If you want a darker red, put on several coats of just stain first.
If you look at some of the guns on his website you can see the beautiful results.
best of luck.