If you're going to destroy the RAID set anyway, disconnect the HDDs, boot with just the SSD, install Windows, reboot and make sure everything is ok. Reconnect the drives, create a new RAID 10 array, boot up and install the RAID drivers in windows, partition and format the new space.
If you were not planning on destroying the data, there is usually no way to convert between RAID 5 and RAID 10, you will need to image the drive to another drive first and then image it back to the new RAID 10 set.
Thanks for getting back to me.
I'm going to destroy the RAID set up, I have all my files back up on a server!
I was just a little confused about disconnecting the HHD's, before connecting the new SSD! I did not want to disconnect the HHD's mine are a little fiddly to connect!
So! I delete the RAID set up, connect the new SSD, load windows, reboot, set up new RAID! Sorted! 0_0