After much soldering....and a little debugging we managed to get the array lit up.

If you look carefully you can see the grounding braid we used as a power and ground bus at either end of the strips. We then simply hooked up data and clock (these are APA102 LEDs remember so are SPI driven) using a pair of wires to create one long strip.

We had some flickering problems to start, but it turned out we had the SPI frequency set to high, turning it down to around 3mhz worked wonderfully. More on how we are driving it to come...