a search based around "software raid" and " LVM volume" did the job and it was suprisingly easy.
mrrangerman, your asumptions were correct, i had an old disk with the FC6 install on it (which died) and two new 160gbs with my dbs and files on.
Firstly i tried mounting one volume but it didn't like that as the file system wasn't correct, so i poked around and came up with a clean solution.
(based on this article: http://www.linuxjournal.com/article/8874
mdadm --examine --scan /dev/hdb1 /dev/hdc1 which came back with
ARRAY /dev/md0 level=raid1 num-devices=2..... etc
then i copied that info into /etc/mdadm.conf
mdadm -A -s
then mounted the array and saved it in fstab.
I think i was lucky in that my orginal array wasn't volgroup00, if it had been i'd have been in more of a mess.
thanks for your pointers.