Thanks - that was enough to help me realise that the peripheral enable needed changing for GPIOB too. Analogue in next...
Obviously I've not tried it yet, but the freescale examples look pretty trivial:
#include "mbed.h"
Serial device(p9, p10); // tx, rx
int main() {
device.baud(19200);
device.printf("Hello World\n");
}
and I need to use 'PTD2, PTD3' rather than 'p9, p10' for the pins. All from one page of the online documentation.