[gnome] Can't sort Nautilus bookmarks

I've just installed Ubuntu 16.04 after using 12.04 for 4 years.

Previously bookmarks in Nautilus were sorted under headings "Devices", "Bookmarks", "Computer" and "Network".

Now those heading are gone, and all the items that used to be in "Computer" appear first. Several of these I never ever use (Videos, Music, Pictures) but they can't be deleted.

This means that my own bookmarks are way down the list and can't even be seen without scrolling unless I use a very large window.

Is there any way of getting some useful behaviour from this bookmarks list? E.g. deleting standard items that I don't want and/or moving my own bookmarks to the top of the list.

David