After a bit of faffing about, I managed to find a datasheet for the 16x2 LCD I currently have. From this ive been able to completely rewire the ribbon cable connecting to it. But the trouble didnt end there!
At first, thinking I had it properly wired to the PIC, my PSU went into short circuit protection! Oops, clearly something isnt right. It turns out that every connection number has the same function on this LCD as on a standard module - except pins 1 and 2, GND and Vss on a standard, are reversed on this one!
That sorted out, it still wouldnt work, and the PIC began to get hot! Oh dear. So, I pulled the whole lot of connections off, and refitted them again one by one, to ensure whichever incorrect pin I had didnt happen again. My reward for doing so was a working LCD! Next step then is to find an encoder (or wait for the one coming from the Far East) and get the control inputs working. Once happy with the inputs and the display, i'll add the expensive part - the DDS module itself!
Ive also today ordered some 16LF84A's for some older PIC projects, and some 12F683's to experiment with. The 12F683 is an 8-pin 8-bit MCU, but is non the less a remarkably versatile and powerful little device! With on board A/D, some amazing low power options, a huge array of timing and clock options, and PWM capabilities.