EastRising 5" tft RA8875 problems loading from SD card

Dear Sirs,

I am using a 5" tft screen from BuyDisplay.com which is made by EastRising.
link

It is a RA8875 shield which is mated to the screen and mounted on an Arduino Mega.

The Adafruit GFX library works fine (as bundled with the screen) using the draw commands but I cannot read anything from the SD card on the shield.

When I removed the screen from the shield, I have no problems reading the SD-card.

I notice that the Chip Select pin for both the SD-card and the screen is the same (10) and they both use SPI interface. Could this be the source of the problem?

Many thanks for any help
/Jonas