As you say you are using LPCXpresso, you may find the LPCXpresso forum as useful place to look for help. In particular this recent thread may be of interest...
http://knowledgebase.nxp.com/showthread.php?t=4730
To actually debug an LPC810 with LPCXpresso though, you will basically need either an LPC-Link (from an LPCXPresso board), or an LPC-Link2.
It's the LPC800 Mini-kit:
You need a suitable JTAG/SWD interface. I used a Rowley CrossConnect with the SWD adapter with their CrossWorks compiler and debugger.