Ok - got a bit confused.
I thought the request was to wipe the contents of MyDocs in order to start again.
Sub-partitions: I thought he meant the partitions made within the MyDocs "space". It seems the new partition was placed at the "beginning" of MyDocs, thereby increasing the size of linux partition.

Also, (apologies for asking but) does fdisk work for moving partitions? It's in the power-busybox.