Mavidon is another source for plain collodion

Hello all,
I use large format cameras, I am becoming increasingly interested in tintypes and collodion processes, I looked at the Mavidon website and it lists ready-made collodion. So this can be used directly for plates?
I am new to this so still rather wet behind the ears...
Secondly, could someone recommend a source to purchase a wet-plate back for my whole plate camera? I am in the UK.
Thanks!
Anton