right so here we go trying to explain this one and find a solution

When my vrs is cold (first start of the day and after work) the electrics have a gremlin but only when cold and for the first 15-20 seconds

Ill start the car and any lights on (headlights dash lights interior lights if doors open) are going dim then back to full brightness then dim in about 2 second intervals

Its not random dimness its got a distinct pattern to it

My first thought was alternator but that wouldnt cause it to be in a pattern like this

Its not my sub causing it through bad earthing i even disconnectex the sub completely for a few days to check and its only when the car is cold

What the hell is going on?????

Check the fuse box on top of the battery for signs of melting & corrosion.

There is connector that clips into a slot on the starter motor bracket. This connector carries the two signal wires for the alternator (and the a/c clutch wires). There could be a problem with the connector or the wires.

Another possibility would be the alternator regulator.

Fuse box looked ok as i checked all things like that

Ill check that starter connection