I was trying to download the sdk file for the LPC1769 but its not on the website.
I'm afraid that there is no MCUXpresso SDK support for the LPC17 family. You need to use LPCOpen instead.
If you are using MCUXpresso IDE, then an appropriateLPCOpen package is included inside the Examples subdirectory of the IDE. See the IDE's User Guide for more details.
For more information on LPCOpen, as well as packages for all toolchains, visit:
Regards,
MCUXpresso IDE Support