found a post with details on the faulty OLED displays – obviously mine
fell into this category!
for completeness to close this post
The replacement OLED display for OS 3.0 AC appears to be:
OLED Display 0.96” IIC (I2C) 128×64 resolution, also sometimes referred to as “SSD1306” .
( which is actually the I2C driver chip used in the display electronics)