What is the meaning of ding-dong in Britain?

Answer 1

I have two answers for this.

1) Ding-dong can be used much the same way cheers is used.

2) Ding-Dong Bang Bang. A much reputed IRA tactic, where a Briton would order a Pizza or other takeout and the IRA would show up disguised as such delivery boy. The IRA person would ring the doorbell(Ding-Dong). And when the Briton answers the door(Bang Bang). The end result can be inferred.

Answer 2

In Britain, "ding-dong" colloquially refers to a heated argument or dispute between individuals. It is often used to describe a lively or contentious exchange, especially in a verbal or confrontational manner.