As others have commented, due to contractual complications, there was a five year gap between the first season (or series as they say in GB) and second seasons of Lovejoy.
Ian McShane comes back with long hair and a bit more trim (I disagree with another reviewer on that account, and I just watched the last episode of the first season yesterday, and this episode today). Lady Jane seems to have lost weight, also. Eric and Tinker look just the same to me.
As is usual, the episode involves Lovejoy uncovering an antiques scam -- this time by being made the fall guy for it. There were plenty of amusing moments in each first season episode, and they are present here also, including a big smile at the end, as Lovejoy enacts the ultimate revenge for his victimhood. :-)
These stories are all clever, and they don't have the same issue that some of the books do. Jonathan Gash (pen name for John Gant) sometimes rushing a flurry of events onto a short space at the end of the books, making the end of those novels a bit hard to follow. You don't have that problem in the TV series.