Dying blonde over orange hair?

So I tried to bleach my hair earlier today and, despite leaving the bleach in as long as I dared and putting toner in after I got mostly bright orange hair with random platinum blonde bits (I think some lingering henna may be responsible). It's technically a disaster except...well I kind of like the colour. However I think it's just the bit too orange to fly with my boss and also repeatedly trying to **** up bleaching your hair is a ridiculous way to maintain a colour. :P So I'll have to dye over it.

My question is would it be best to go with a copper colour or could I try dying over it with blonde? I'm planning on using the brand Naturtint (I'm vegan and it's the only readily available vegan dye near me). I've used a few of their copper dyes before on brown hair and have always had decent results so think if I were to use them on this they'd work fairly well to tone it down and give me a more natural colour. As I have never used their blondes though (or any blonde dye for that matter) I don't know what to expect. Looking at their site I can't see why it would cause any issues provided I don't try dying it any more than two shades lighter than it is but other places are saying using a blonde dye over bleached orange hair will only result in an even brighter orange which is the opposite of what I want.

So is it safe to try blonde or should I just try tone it down with copper and attempt bleaching it again after giving it a few weeks to heal.

Also before someone suggests going to a professional, I would love to but I don't have the money for that right now unfortunately.