backing off float too soon

So we had a little incident today. I'm rather concussed so I apologise if this rambles.

Background:
Prin used to take 2 hours to load. That was fixed. Now she walks on beautifully with at most a tap on the back.

Recently she's stared disembarking prematurely. I wouldn't say she's rushing she just walks herself off before being given the ok. The first few times she did it a push or a tap on the bum was enough.

My float has a VERY steep ramp which took a bit of getting used to but now doesn't seem to prove an issue.

It has a breeching door.

When the breeching door is opened she just walks off without being asked. The last few weeks I've then sent her straight back on with a little argument.

We float untied. I have been leaving the chains off incase she ends up going under.

Whats the best way to fix this?

Today she came off and I went to fix it as usual but she caught her foot on the door then obviously reared up and knocked me over in the process.

My friend watching said it was one of those things but it was definitely caused by her wandering off early.

How do I fix this.

I did put her back on after the drama, ran and got the carrot stick. Had her stand there for 10 mins with other horses milling around but id like to be able to wean off the big stick!

The way Clinton Anderson teaches to do it is make it rest in the trailer and work outside.....I would put a halter/lead on her. Do a search on Youtube for Clinton Anderson and I'm sure there are vids about trailer loading that would be helpful to you.......

She wears a halter/lead just with the rope over her neck
I think its similar theory to what I've used to get her on /stop rushing off. Tapping intensity increases as she backs off, diminishes as she get on up to quite hard if needed. She is a red headed mare and circles simply hype her up

I don't think it helps that I'm exhausted after hunting so I was a little lax the first two times it happened.

When she hasn't been anywhere I can have her stand in the float up to half an hour at a time (after that I get bored :P). It's just transferring to actually being somewhere. I think I'm going to have to carry the carrot stick for a while.