I have some pictures of a Plus 4 dash that may help.
Thank you very much for the pictures!
Next week I am going to the Morgan Centre Sweden and have it fixed. Then I am going to take some photos from behind the dash. May be it will differ from +4.
If the LED is soldered direct on the circuit board, then it can be unsoldered and lifted up to put a wire to the LED.
If this is impossible, I will bring a light conductor to see if it can be used instead.
To put an dumb flashing LED in the dash, I do not see as an alternative, as one then have to have a separate switch to switch it of under driving conditions.