Lude Generation

Came upto a set of lights after a tunnel run and noticed the car had a very noticeable misfire.

Car has new plugs which were properly gapped when fitted. All leads nice and secure.

Before I start changing leads and potentially a distributor is there any obvious things I'm missing?

Has it dropped permanently onto 3 cylinders or is it an intermittent miss?

It is very intermittent.

Even when it happens, if i drive it normally for 5 minutes then the misfire stops.

Coilpack?

As in the igniter coil in the distributor?