Saving but not publishing

Have you tried emptying cache hard by hand? (deleting all in the cache folder by hand)?

I think you were right with that, I wasn't able to delete the cache as it said I didn't have permissions but I've got the host to do this for me and now all works fine! The cache had obviously got frozen somehow.

If you have to call the host to delete the core/cache folder manually every time, you're going to be in for a lot of host calls over the life of your site.

This should be as simple as either ftp- delete (which is slow), or opening the file manager in your control panel and deleting core/cache files.

Here's a thought... you should be able to manually delete core/cache through the file manager in MODX.

I'm guessing the files were assigned to the wrong user cause of the server move, preventing MODX (ie PHP) from deleting the files.

The host had just upgraded their server to a faster one and I think in the move some permissions had changed, so hopefully it's just a one off.
I hadn't thought of deleting through MODX, I' tried cpanel so will try that if it happens again. Mark you are right though.