Yes, I know Lovejoy both from the books and the TV series. I can't remember which I came across first. Probably the books. I'm re-reading them at the moment.
I like the books, but Lovejoy certainly isn't loveable, with his violence towards anyone who gets between him and his passion - antiques. I found his casual violence towards his lovers most disconcerting in the first couple of books on re-reading them.
See here for my 'as I read them' reaction.