When installing 10.1 it installed grub to mbr on my first hard drive, though I thought I had told it to install to partition (/dev/hdb1). I assumed I must have chosen mbr by mistake, til now.
I installed my kanotix bootloader back onto the mbr then booted into suse and used yast to tell it to install to it's own partition. After rebooting I found it had overwritten my kanotix grub on the mbr again.
So again I reinstalled kanotix grub to mbr and went into yast to install suse's grub to it's partition.
I did this four times and every time it installed it to mbr.
Well, a couple of hours ago I moved my suse install to another partition and told yast to install grub to the new partition and again it installed to mbr.
I eventually gave up and used grub-install (I had tried before but got command not found so assumed I couldn't do it with suse but I found it was in /usr/sbin)to install to it's own partition
and it finally worked.
Another bug?

I agree. Report it to SuSE. I still use 9.3 Pro. And I haven't seen such errors.