Update AEBS (4th Gen) and AE (2nd Gen) stops working

Hi

I have a Virgin Media Superhub 2 and connect my Airport Extreme (wired connection). My Airport Express is connected wirelessly to extend our network. The 'Apple' network is separate from the VMS2 networks.

If I make any changes on my Airport Extreme - like change Access Control setings, the Airport Express stops working and can only be used again if I do a hard reset.

I must be doing something wrong. Is there a better way to do this?

Many thanks in advance

Matt