success after four days of trial setting up dual boot on a mini9.
the pre loaded dell variant of 8.04 can only be reloaded from a dell "return to factory spec" disk which formats and leaves Ubuntu primary active in a single partition. [as delivered] attempts to install xp second, which also wants to be primary and active, went off the tracks. Installing xp first in to a partition half the HDD and regular 8.10 Ubuntu in to the largest unused space put Ubuntu and a small swap partitions in an extended partition. Ubuntu & grub worked perfect. I found I had to abandon the Dell variant which would dual boot with other linux, just not MS.
PS and I only needed XP for Quickbooks