TracyJ New collector 828 Jug

Hello, I am still learning to navigate the site and am a new collector. I was wondering if anyone could help me identify when these jugs were made. 
The brick/red has 828 on the bottom and the Yellow has 6016 on the bottom.
Thanks for your time.
TracyJ

Generally speaking the change from three-digit numbering to four-digit started at the end of 1964 but some shapes were still made with their three digit numbers after then, perhaps only changing to four digit numbering as new moulds were made or slight modifications were made to the shape.

The four-digit jug is part of the “Shape 25” range (the 25 is spelled various ways) and this one was introduced in November 1967. Ev has put dates in the gallery as she encounters them in Crown Lynn records. See here:

https://www.newzealandpottery.net/gallery/Crown-Lynn-Shapes-Catalogue-with-Four-Digits/Jugs-Earthenware-and-Vitrified-6000-6899/6016-Shape-25-1-1-2pt-Jug-15cm-Nov-67-pic_3794.htm

Thanks Jeremy, I found the Gallery, thanks for your advice and thanks to Ev for all the work I'm sure it takes to set them up.
TracyJ

TracyJ that red jug is very special. I have seen a couple in the creamy clay with a clear glaze, but I have never seen one in the red. The shape is a direct copy of an English Meakin jug, not the first or last time that one pottery has copied the work of another.
Kind regards
Val Monk