Our only clue to the guns age is the 5 hown in one of the picts,which if its a 50,000 series puts it between '06 and '12.
Great years for Brit guns.
If the case is leather or oak&leather and is contemporary to the gun and has been renovated its worth about $1k. Its sad when someone talks about a maker's case like it really was something the maker made,but if it is a case from that era it has some value,especially if the label is vintage and correct to the guns age.
So the gun doesn't have to be worth all the asking price,but as someone else pointed out you probably will never see your money out of it if or when you sell it.