electrics Power to radio at ignition position 1

[scratchabout]

With all previous cars I have had power goes to radio at key 1st position. In my Meriva A power only goes to the radio when ignition key is a 2nd position and all the ignition lights are on. Not a status I wish to leave the car in when listening to the radio whilst pulled up for a short time.

The car had a Clarion CZ fitted when I bought it, works well and the steering controls function correctly.

Have found at ignition position 1 windows, sunroofs and wing mirrors have power.

How can I get power to the radio at the same time that it goes to the windows, sunroofs and wing mirrors?

Splice the radio power line to another cable?

I have wiring diagram for the car and a small amount of knowledge about electrics. Also practile abilities.  Am old enough to accept that my knowledge is enough to create dangerous unintended consequences...

Any advice/guidance much appreciated.