What event in Chapter 43 gives us a clue that Orlick may have been the one waiting in the sluice house?

Turns out Orlick was there the night Pip met Drummle,

"I saw him through the window, seizing his horse's mane, and mounting in his blundering brutal manner, and sidling and backing away. I thought he was gone, when he came back, calling for a light for the cigar in his mouth, which he had forgotten. A man in a dustcoloured dress appeared with what was wanted - I could not have said from where: whether from the inn yard, or the street, or where not - and as Drummle leaned down from the saddle and lighted his cigar and laughed, with a jerk of his head towards the coffee-room windows, the slouching shoulders and ragged hair of this man, whose back was towards me, reminded me of Orlick."