Basically my 99 type r has a 6 speed uk non-dccd box in it

We left all the dccd ecu/roller etc in the car if I should ever change to a hawk 6 speed dccd box.

Went out in it today, about 100 mile journey and 20 miles from home I notice the bottom green light (diff open) blinking steadily.

This is the 1st time I've ever seen a light up on the dash, and as the box isnt dccd I'm curious whats causing it.

Would I be right in saying the dccd ecu is in the dash by the steering column?

 

If there is no connection to the DCCD ECU it will act the same as the electrical circuit of the DCCD being broken which is to flash the bottom green light.

You are correct on the ECU location.

 

Strange thing is, I've owned the car 18 months and never ran it with a dccd box in it, and its only now the light has appeared. Nothing has been changed so it sounds like I need to remove the ecu or unplug it

 

there is also a plug in the console near the handbrake, it hasn't been connected by any chance?

 

If your box hasn't got dccd then you will have a plug that's not connected to anything. I'm not sure but sometimes people fit resistors to things to keep the light off and perhaps the same was done to yours and it might have failed.

We can only speculate, you need to have a dig around the connectors and determine how it's been done then start troubleshooting.

Does the indicator for dccd function when you move the wheel?
Do you normally have it in auto?