How do I reinstall LL safely in a win7/zorin/lubuntu/LL multiboot?

[m654321]

My young son expressed a wish to have Lubuntu14.04 & LL2.8 added to his win7/zorin9 dual-boot [see setup (3) in signature below], which I've now done. However, I need to delete & reinstall the LL partitions on this multiboot system.

The situation doesn't seem (at least to me)  to be as straightforward as a win7/LL dual boot. With win7/LL I would use the win7 repair disk and enter the commands bootrec /fixboot  and then bootrec /fixmbr in the command prompt (X:\Sources>), following deletion of LL using gparted. After that, LL (or another OS) can either be safely added to win7 or win7 simply left as a single-boot system.  However, I don't think I can do that here as I have more than one distro booted with win7.

As I wish to remove & reinstall  LL2.8 in a win7/zorin9/lubuntu14.04/LL2.8 setup, can I merely delete LL in gparted and then simply reinstall it.  As I'm replacing like-with-like, I'm assuming the grublist or win7 bootloader wont get messed up - is this assumption correct or is there another method to do this?

Thanks for any help on this one.
Mike