DAVE: Lane, think about this, do you really believe this is working?
LANE: No, it’s not working. We sound like a bunch of wankers.
Wanker, offensive British slang literally referring to someone who masturbates, used to mean someone is stupid, foolish, or unpleasant (often obnoxious or arrogant). I’m not sure if Lane realises how offensive the word is, and may be using it as an approximation of “jerks”. I presume that rehearsing “London Calling” has inspired the use of British slang.
The Annotated Gilmore Girls 