Hello Simon,
I will try to respond to your comments one at a time...
Yes, it was a typo and I know that OES is supposed to be one SP behind SLES. It should have been SLES11SP3 and OES11S2.
>You can safely disable the above two via "zypper mr -d 1 2" as these relate to the media and not online repos.

Great have done that successfully.

>If the server is SLES11 SP3 (with or without OES11 SPx) then you can safely remove all the SLES11 SP1 and SP2 repos which will reduce your
>zypper lr output!

That's good to know.
>If you haven't yet upgraded your server to SLES11 SP4 you should not have these repos added or enabled.

Right, well I've not yet upgraded THIS VM to PS4 due to warnings I was getting.

> As I don't want OES on this VM, am I safe to ignore the warnings, accept
> warnings about removing OES and proceed with the update to SLES SP4?

>Ignoring whether you still want OES on this VM does it currently have OES? If so, you can't simply elect to not upgrade it but will first have
>to remove the server from your eDirectory and then remove the OES components. Then you can upgrade the underlying SLES11 SP3 to SLES11 SP4.

I've had a look at my eDirectory, and the ONLY server it shows (as I expected) is my OES VM (named "vm1-oes"). The other two VMs are purely for Groupwise (vm2-gwise) and Groupwise mobility service (vm3-gms) respectively: neither of these are in eDirectory, and neither of them needs OES. EVEN THOUGH both were installed using the same SLES11SP3/OES11SP2 DVD.

So if I read your advice correctly, I should remove the OES components on these two VMs. I guess it's not possible to do this by simply removing the OES repositories, so what would be the steps to do this? Perhaps I need to take this to an OES forum?

Thanks for your help already.