Hey @drippygfx! Welcome to the forums!
I don’t know that we’ll be able to help you with this amount of information. Can you give us more to go on? This isn’t something that would normally happen so anything you can give us would be helpful! For instance, if you resized these meshes, did you save them afterwards? Are they imported/saved/reimported/not saved? Where did they get imported from if so? Are they all supposed to be together and were sized up relative to the gizmo and the gizmo didn’t move (anchor point is same) or did the gizmo move and the items didn’t (anchor point altered)?
Get back to us with some more info soon! 
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Hello, this is what it looked like before if it helps. Some of the meshes were imported from Fab, whilst the walls were made using the modelling tools. I did scale them though they were never as big as they were now and as far as I’m aware it should have been saved. The anchor point isn’t affected but the gizmo is showing where the object should be.
So if they’re actors, try selecting them and adjust the static mesh position relative to the parent.
If they’re just static meshes, you can use the modelling tools to adjust the location of any part of the static mesh, including place the Anchor where you want (the Gizmo is always shown at the anchor point).
It definitely sounds like a saving issue. You have to save the level, and save the individual pieces, try using “Save All” before closing out.
I’d try a few things on one individual piece, close and reopen until you get something reacting correctly! Then you should be able to do the same to the rest.
Sorry it didn’t save as you placed the items. 
If I had a nickel…