Make gold update every minute.

[Velocity2k]

For example if a team almost kills 2 enemy heros at 4:20-4:55 as opposed to 5:05-5:35 in the first instance they readily get the gold as when the latter happens they must wait 4 whole minutes to get the reward of killing the enemy heros.

First of all if you "almost kill 2 enemys" you don't receive any gold at all. You only receive gold for actually killing them.

Secondly: If you kill an enemy you instantly receive the gold. You don't have to wait at all.