Scaling multiple objects at once.

[Vectorspace]

When you select multiple static meshes and scale them, each scales according to their own centre.

So if I have an object built of multiple static meshes, I cannot scale it as a whole.

Is there a way I can?

[pingfreak]

try placing a pivot. right click on a verticy and select pivot.
or hold control, left click ( on a verticy ) will set the pivot.

[Vectorspace]

That works when I use the scaling widget to scale, but I want to use the number boxes at the bottom so I can scale by a specific factor.

In addition, if one of the objects has been rotated its axes will not be the same as the others, and will scale in a different direction when I use the non-uniform scaling widget.

[DGUnreal]

I haven't tried this... if you make the group of meshes into a prefab does it all scale from a single origin?

[Vectorspace]

What does it mean to convert them to a prefab? Does it save them as a single static mesh (and therefore must be packaged with the map as a new object) , or as a collection of separate pre-existing objects?

Can a prefab be exploded back to its constituent parts?

[xerofighter]

a prefab is bsicly a collection of meshes under one single reference
a prefab will be saved in your <fillinmapname> package

It can be broken apart yes,

[Vectorspace]

That will be very useful!!

I will have a play with it.

[DGUnreal]

If you have used a grouping feature with any 3D or paint software, the prefab is similar. It groups all of the meshes into a single unit in the package you specify (usually your map file). This is handy for those times when you have something like a building that is created from a bunch of mesh parts, you can prefab it, then place it multiple times into the map easier.
However, as mentioned, I don't know if the first or last object chosen becomes the origin axis, I never tried that yet.