Judging by the amount of soot that was on the burner I guess the previous owner had one unsuccessful attempt at lighting and thought better of trying again.
@fishfish they are fairly straight forward to light, you just need to make sure the preheater shroud gets nice and hot before you drop it down into position. There's the little hooks that allow it to be fixed in the raised position whilst it warms up, once it's warm, drop it down and it will draw air properly and preheat the burner. If it's dropped down too soon then the flame will not be intense enough to heat the burner, it may even self extinguish.
fishfish - I have never actually tried lighting a BR49 / BR49A. But the advice from Matthew above sounds like a good tip.