When more of the squaremap is rendered when players roam, it loads in the new sections in a "splatter" more than a consistent block of map

I.e. the majority of the newly explored area remains black with a few random blocks of coloured in map - if a player continues to move around in this area then a few more map chunks render, but it takes a long time and is inconsistent

I have already loaded in a large radius using Chunky prior to adding this plugin

You would have to execute a render command (radius or full) to fill in the gaps.

This is because you have used Chunky to pre-generate chunks. Now only updated chunks are rendered, and that gives you the "splatter" look.

Normally, any new chunk is rendered when you are exploring, but the chunks you previously generated with Chunky are not new to the server.