Making Directions Plum Brighter

Hi everyone, I'm a bit of a newbie to hair colour, so I'm sorry if this question is a bit stupid.

I really wanted to get black hair with ombre purple, my natural hair is dark brown, but I'd had red hair before this. I wanted the purple to be bright (to be able to see it without having to stand under a light, have flash on my camera or in sunlight). I went to the hairdressers, and she bleached my hair and put directions violet over it.

However, it' didn't go bright at all and you could only see it underneath the light. When my hair was bleached, it did go quite blonde, so I don't understand why it did that. Anyway, she suggested going over it again with the violet, and I did, but it didn't do anything again.
Oh, actually the underneath parts of my hair went really nice and bright, but the top parts which everyone can see hasn't done much at all.

I asked for some help from some other friends and they said plum may be a better colour to go for if I want a bright purple. I tried that today and it has made a small difference in colour, but it's still pretty dark. I actually diluted it with a lot of conditioner too to make the colour brighter, but yeah, nothing really happened. Again, the underneath is lovely and has gone even brighter, but the top hasn't budged.

What do I have to do to make the purple brighter? I really don't want to bleach it again, I don't trust myself at home and really can't afford to go to the hairdressers again to have it done 🙁  but I've heard that directions is just a stain dye, so even if I keep adding more colour it won't make a difference. Is this true? I just want to make sure I'm not wasting money and time that's all.

*thx*