DANG SPI!!!!!

Sorry... It's a Uno (non R3)

SRAM 2 KB (ATmega328)

I'm beginning to think that I am running out of memory...

Maybe. I count 509 bytes in static strings (you really should be using the F-macro) and 60 bytes in globals. But I don't know what these add...

RTC_DS1307 RTC;
File logfile;
RF24 radio(8,9); //Radio pins 3(to8),4(to9)
RF24Network network(radio);
serialGLCD lcd; // initialisation

I suggest introducing the F-macro to your sketch to reduce that 509.

Which devices are SPI?