Trying to get RL-FlashFS working on LPC2300

I'm building some code to read the SD Card on an MCB2300.   I'm using the RL-FlashFS library.

I have configured CCLK to 48MHZ and PCLK_MCI to CCLK, and changed the #defines in MCI_LPC23xx.c to read:

#define __MCLK    48000000
#define __CPUCLK  48000000

My code to initialise the card reads:

	uint32_t retv = finit(NULL);

The SD LED on the MCB2300 board comes on when the call is made and then there's a *long* pause and eventually the function returns a value of 2.

I'm using 4.74 of the library and uVision 5

Help please, I am totally baffled.

Thanks, David