Many thanks for all of the replies here! I didn't run off to compete for the Darwin awards
Lurking in the forums here for a while now and I can see why you would be anxious about people who are just wanting to jump into this.
Upon more reading I have posted this in the wrong section of the forum as what I am intending to make is a melting foundry as opposed to a forge (although that may end up being a later project). I also understand that each come with their own risks, this particular PDF was highly useful! http://prometheus-foundry.com/The Hobbyist's Guide to Casting Metal--2nd Edition (web).pdf
This might be the reason why you thought the dimensions seemed on the large size; I am looking to hold a 0.75L A4 graphite clay crucible in it with the possible option to increase the size of crucible when I am confident at working with smaller volumes of liquid metal. As it turns out the canister is smaller that I had initially thought as well.
Attached are some quick digital model images with dimensions of the materials I am working with and what I intend to make them into.
Many thanks, Frosty, for your advice about boiler service companies! As it turns out a friend's father works as a boiler-man for a an industrial unit and procured me some ceramic fibre wool which he uses for insulating their industrial boilers. After checking the packaging it seems it's rated to the same 1260 Deg C as the wool I was looking to buy so that saved me some pennies.
As I stated in my initial post, the inner hot face will be refractory cement followed by ceramic wool. My process will be to clean the inside of the canister with a wire wheel before using a ceramic wool adhesive to attach the ceramic wool. Once glued in place I'll use a rigidiser solution to stiffen it up before mounting a form on the inside so that I can pour my cement in between the two. The final layer will be one of a zircon paint to help reduce corrosion from any eventual crucible failures.
If you have any constructive criticisms about the design they would be most appreciated.
(I also bought a tonne of PPE. Looking back it is absolutely ridiculous that the inspiration for this, the kingofrandom, uses none whatsoever...)
Once again, many thanks!
Seph