Connolly Hide Care is what I've always used. It's sometimes called Jaguar Hide Food, but it was made by Connolly and the correct name is Hide Care. I've always got mine from the Jaguar dealer, but you could probably get it at a Rolls or Bentley dealer, or mail order it, now that it's on the market again.
The Connolly hides in my Xj12 look terrific. The leather in the Xj8 looks good, but not as good as the Connolly hides in the older car. The leather in the Torrent GXP looks good for a cheap car, and has brushed off the insults of child and dogs. The leather in the Solstice still looks like new, but its hardly been driven. It's a soft leather, comfortable, like in the Torrent. The leather in my G8 is wearing well, but it's a hard leather that has always looked cheap to me - not nearly as nice as the terrific pigskin style leather my GTO had.
There is another product called Gliptone, but I've not used it.