The
WATCH list lists herself as copyright contact, so I don't think that she currently has a literary agent.
At Amazon UK, the (five, since 1995) volumes of the Merlin series are available individually, all published by Hodder in 2012. (At reasonable prices of £3.95 for the first and £2.48 each for the rest.)
It seems unlikely to me that Hodder have non-exclusive UK right, but it's just possible that the Smashwords one is legit. I'm just not tempted without a lot more info on it.
I disapprove of pirates posting things freely in torrents. I really hate pirates who try to profit from their piracy.