Mr. 470evans:

It does not appear to be a steal at that price, unless the workmanship is exceptional. Trouble is that, not being all original, it is more of a custom rifle than a collector's item. Nothing wrong with that if the rifle is what you want. I happen to be a big fan of custom single shot rifles...

You could have a pretty nice rifle built to your specifications for $6500 or a bit more, although without such extensive engraving. So there is one way to put a value on it. If you were going to have a $6500 rifle built, would this be it?

On the other hand, original British actions are not exactly thick on the ground here in the US. Nor anywhere else, apparently.

Does the action have a tang safety or side lever safety? If the latter, is it bolted in the up or down position?

Best of luck!

Glenn