It usually is considered polite to offer a taste of the wine to either the sommelier (if there is one), the server, or the chef.
How about bringing a bottle just for the three of them? Then going back in the kitchen and helping them clean up ? Maybe even staying late to lock up?
Listen, no one expects a taste of your wine from you, and most restaurant employees know you are doing it specifically to knock the corkage fee off your bill. I see this practice as extremely patronizing and think that offering wine from your table to your server is absolutely unnecessary, unless you know them and they know you, and you have an established relationship. These folks work in a restaurant business, for crying out loud, and they see more wine going by than many of us ever will. If you don't know them, pay up the fee and enjoy your evening with friends, relatives or whoever is dining with you. Don't waste your time on trying to scheme a tenner off you bill. That said, I'm not suggesting refusing to discuss a wine if your server recognizes a gem brought by you. In that case a small pour and a brief exchange are appropriate. In other words, let them come to you, don't fall over yourself trying to please your server with a taste of wine, it only makes you look needy and/or cheap. YOU
are the one to be pleased there. Let them do their job and always treat them with respect, and please, don't over tip, it spoils good people.