I'm quite sure we are looking for a british couple. Why? let's start:
Some answers were already given:
333666... = "FOLLOW THE STEAK SAUCE TO SEE WHO WE MIGHT BE".
19! = 121645100408832000
Let's countinue with the latter:
18 digits.. could we somehow interpret that as a coordinate?
Maybe if we split that up to 2x9 and add two decimal points?
121645100 -> 12.1645100
408832000 -> 40.8832000
leads us to somewhere in ethiopia, afar region. At least we found a desert. Horray :)
But hey, there's a A1 nearby. And since that is a quite popular brand for steak sauce, let us follow that sauce.. eh, road.
We end up in Addis Ababa. Luckily we have to fill a 2x5 grid:
+---+---+---+---+---+ +---+---+---+---+---+
| | 3 | 4 | 5 | 7 | | | 1 | 2 | | |
+---+---+---+---+---+ +---+---+---+---+---+
a d d i s a b a b a
With that we get "baddi_s". Might "baddies" fit?
Baddies... Somehow (beeing a german with a strong addiction to british humor) that reminded me at a sketch of two guys, asking themselfs "are we the baddies here?"
So I'm left with a last question - does my assumption fit?
It does. =)
_ _ _ _ _ E _ _ _ _ D _ _ _ _
M I T C H E L L A N D W E B B
Therefore, I'll go with
Mitchell and Webb
https://en.wikipedia.org/wiki/Mitchell_and_Webb
additional link:
https://www.youtube.com/watch?v=ToKcmnrE5oY