I managed to solve the problem by adding a 1K resistor (I didn't use 2K2) and a 1N4148 diode according to this schematic on the E (SCK) and RS (CS) line 
It's a nasty little hack but it does the trick but shunting the current on the E pin when RS is active so the SPI is basically disabled thus preventing any garbage being triggered on the screen. A better solution would be to use a spare I/O pin and use a transistor to drive the E pin I guess. Again, it does the trick though.
