Far too many rifles to list now, all mainly British but the odd pesky foreigner has snuck in
Yes they are and as yours is in .177 then even more desirable, I managed to buy an early one in a gun shop in the early 2000s for £100, the "S"s where better quality finish wise than the standard models and they also had better features like 2 stage metal trigger (plastic on standard), adjustable breech bolt, walnut stock and the thicker section 17mm barrel (standard had 15.5mm), I'd say around about £200 is a fair starting price, so the £230 trade in price you've been offered so far is pretty good.
Pete
Far too many rifles to list now, all mainly British but the odd pesky foreigner has snuck in