Pauillac. Age dependant on the seasoning, if heavy on garlic and herbs then you want wine that is still adolescent; if light on seasoning, I’d go for mature ( but definitely still fully alive).
Another consideration would be source of the lamb and how strongly flavoured it is. There is quite some variation.
I would determine the side dishes after I’ve picked the wine. The grander the wine the simpler they should be.
But all the comments above about baisically going with your favourite red are not wrong. I’d just say focus on mid weight wines. A block buster fruit bomb would run right over the lamb, and convesely a light Pinot would get lost.
Mint sauce puts me in mind of of the dodgier kind of club dining room or (English) railway hotel. If using not sure what I’d do with the wine other than significantly drop the budget and the age. Young medoc lmaybe. Cab Franc even?
I made that tonight for Xmas Eve, with roasted potatoes and steamed haricot verts. Cracked a Maison Dujac Gevrey Chambertin 2013 that went great with it.
You have a lot of good choices. I’ve had leg of lamb done with mint, rosemary and garlic twice this year, once with aged St. Julien and once with a Côte Rotie and a CdP. All were good, but with the '81 St. Juliens it was for me on another level.
Thank you all for your ideas: You actually changed what I was planning. We ended up with claret and CdP, with a Barolo at the ready that in the end was not needed.
We started with 2007 Vollenweider Wolfer Goldgrube Riesling Auslese with the foie gras. Delicious, very ripe and sweet, with enough acid to balance the foie (and helped by the sherry vinegar dressing in a little side salad). Still has a long life.
Then with the lamb, accompanied by the stuffing, roast potatoes, roast brussels sprouts and glazed carrots, all with an incredibly rich lamb gravy, we had:
1989 Ch. Leoville Las Cases – beautifully mature (to my taste), with enough fruit to still be fresh, but with clear secondary development on the nose (leather, sous bois, a bit of spice). On the palate, tannins resolved, red fruit, along with enough acid to still taste fresh. A lovely bottle.
1998 Clos du Mont Olivet CdP – Again, fully mature, with dried fruit and flowers, leather and spice on the nose. The tannins were fully integrated and the mouthfeel was quite soft, with dried cherries and a slight smokiness. Another lovely bottle, although it faded a bit towards the end.
I opened them both about 4 hours before drinking, and served them cool (16-17C). The 1997 Altare Barolo lived to fight another day.