I think I have an environment issue as I can mount using a different client and entirely different config but when I try this new client for some reason NFS mount always fails. Below is the serial output I get when the failure occurs:

I am running Fedora v12.

-------------------------------------------------------------------
VFS: Mounted root (squashfs filesystem) readonly on device 1:0.
Looking up port of RPC 100003/2 on 10.1.1.20
Looking up port of RPC 100005/1 on 10.1.1.20
VFS: Unable to mount root fs via NFS, trying floppy.
VFS: Cannot open root device "<NULL>" or unknown-block(2,0)
Please append a correct "root=" boot option; here are the available partitions:
0800 312571224 sda driver: sd
0801 31 sda1
0802 0 sda2
0803 8192 sda3
0804 262144 sda4
0805 0 sda5
0806 8192 sda6
0807 262144 sda7
0808 131072 sda8
0809 524288 sda9
080a 294912 sda10
080b 135725447 sda11
080c 294912 sda12
080d 171914160 sda13
080e 3145728 sda14
1f01 261120 mtdblock1 (driver?)
1f02 4096 mtdblock2 (driver?)
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)
Core of 0 bytes written
Rebooting in 3 seconds..! 00000000
00000000 #@Initializing Nand Flash:
-------------------------------------------------------------------------------

Some problems with RPC and portmapper, it seems. Read more about NFS and RPC/portmapper and see whether your setup provides all the needed functionality.

Thanks, in the end it was just simply I needed to update my etc/exports file as my rootfs location had been changed.