Have i mixed up my tomato seedlings? HELP!

What varieties are you growing and are they labelled?

They look like indeterminate types to me, with big side shoots. It always surprises me how quickly they grow, I try and nip them out every day whilst small but I found a large one yesterday I somehow missed at the top, as big as the main growing tip. Be careful taking the side shoots out, they still should snap off even at your size.

 

Side shoots grow at the point where a leaf joins the stem.

 

I see your problem. The tumbler should be easy to recognise, much lower and bushier. Put those to one side and all the rest will be indeterminate. I know that sounds obvious and maybe there isn't a noticeable growth habit difference yet.

 

These are the side-shoots you need to remove:






On the middle one just check there are flowers coming on the main growing stem to the left, there do look to be but hard to tell from a photo.