British Military - Cookers, Trailer, Hydra type

In the 1939 edition of the Vocabulary of Army Ordnance Stores , it lists
Cookers, Trailer, Hydra type.

I wondered if anyone has any knowledge, info or images on this, please.
Hydra made the No 1 burner, shown below

Full VAOS document is here

 

Search Results for Query: Hydra | Classic Camp Stoves

 

Are you writing a book?

 

Nope. Here's one of my websites, which is mostly about the trucks I drove in the army
Alvis Stalwart & Bedford Files

I'm familiar with the No. 1 and No. 2 burners. I got curios about the cooker numbers because the latest is No. 12, which lead to this as I pieced it all together,
British Military Stoves.pdf

Which lead to this webpage

https://sites.google.com/view/alvis-stalwart-hmlc-files/british-military-portable-stove-cookers

 

Top results are this thread. Can't see anything in the other results about this

 

Are you saying that you read all the posts that @kerophile posted, and found nothing to help?

 

I see no "Cookers, Trailer, Hydra type" in those results