Maybe I'm doing something wrong but sometimes when I go to create a new thread or edit an existing one to add a video, the embed icon will not appear in the above even after I've tried restarting the thread. Anyone know what I'm on about let alone how to fix it?

Depends, usually when I try to create a thread, it isn't there (sometimes there is though I think), but when I make a normal thread reply, the Icon is there usually.

Nope, on an actual PC

only appears in rich text reply for me.

Only appears in rich text reply the first time. Not when editing an existing post.

I usually make a new reply, insert the video there, click on edit html source and copy the html code over. (and cancel the new post)

It doesn't exist when you create threads (my experience).

Just copy in the embed code, create thread, click edit, and then resubmit, generally works.