"it gets to about 99% then gives me an http error" - this does sound like some kind of error on your client or server. However if you individually report the HTTP error and can send a screencast going through the browser's network inspector to look at all the response details for the upload AKAX request, I could take a look. You'd need to open the inspector before you start the upload, and show all the headers and the full response data.

I can deal with the rest though.

This is a combination of a couple of subtle bugs, and misunderstandings.

"The filesize wasn't detected"

Code assumed allow_url_fopen PHP option was on even though we explicitly turn it off. I've re-implemented detection is a safe-way, using our own downloader.

"and seems to revert to 16k"

I think 1.6GB actually. And that's actually due to a bug, this is basically a random number we use for inline editing detection. Fixed.

"The filesize is being shown at 107KB though"

The option is in bytes, not KB - so this is a misunderstanding.

Yeah but 109398KB is 107MB, not 107KB as shown under the download link. It's not showing 109398KB. It's converted it to MB but is still saying KB.

Where's "109398KB" entered though, as the input field is in bytes, not KB.

Yes, input of 109398 equals output of 107KB. I assume I didn't need to add kb to the end of it.

Oh, bytes. That explains the confusion here and I didn't see bytes in your previous reply (read it as kilobytes). Guess I need to google how many bytes are in 109398kb then.