Does anyone know what the trays called that the flowers are sat in?

It looks like a chocolate mould. 

I have one that I use all the time. I got it in the paint section at my local craft store. I believe it's called a paint palette.

Flower cups or flower formers. Some of the flowers cups are individual, others come in trays like this.

AFab thanks. Will have a look on eBay :)

They have them on sugar craft also, they call them rose bud helpers.

AFound loads under paint palette and flower formers. Thank you. One other thing, last time I made some sugarpaste butterflies, I bent some card up to make a wave former, will card be OK or should I use plastic? Thanks again, you're all so helpful :)

I use card stock to make hundreds of butterflies for my mom's 80th birthday party.  Just make sure your fondant/gumpaste is not too wet so that they don't stick to the paper.  You can line it with wax paper or dust it with corn starch.  Also moving them around some as they dry will help so that they are not just in the same place the entire time.

AWe made hundreds of butterflies and used clean, fresh pizza boxes cut Into strips and folded to form them. But I agree that looks like a palette. I have a few I use for mixing paints and forming flowers. If I have a real thin flower that doesn't weigh much, and dozens to make, I will use foil squares and mash them into the cup, then take them out and put them on a tray.

ACool, thanks. I'll carry on using my home made card waves!