Help - want to go platinum, hair disagrees

Hi! New here, hoped some of you knowledgeable people would be able to give me a hand. I'd like to get to a platinum blonde, and my hair really isn't cooperating.

Naturally, my hair is a kind of mousy brown. December 2012 I dyed a blonde streak into my fringe, then left it to grow out until August 2013, by which point there was about 3-4 inches of regrowth and about the same amount of blonde in the front. I then dyed over the whole thing in Manic Panic Vampire Red, which gave it a really lovely deep pinkish red colour with bright pink in the front (1).

Kept it like that up until recently, re-dyeing it every month or so. At the end I left it to fade to what I thought was close to my natural colour, as I wanted to go platinum. About two weeks ago, after reading around a little on this forum, I did a coconut oil soak then put 30 vol bleach straight on my hair and left it for around 40 mins. After this, as was to be expected, my hair went totally fluorescent pink with about 2 inches of bright yellow roots where my natural colour had come through (2).

Luckily my hair was still in a pretty reasonable condition, comparable to how it was before. To fix the colour, I used Colour B4 Fashion Colours and ended up ginger with blonde roots, with a bright white section where my original blonde streak had been (3). 10 days later, I did a second bleach bath with 30 vol bleach for 60 mins, which has now lightened my hair a little, but still nowhere near where I want to be. I'm left with pale orange with blonde roots, and the pink seems to have reoxidised a little on top (4).

Thank you for getting through that - what I want to know now is what should I do? Another Colour B4 to get rid of the remaining pink, then bleach again? Or just try a series of bleach baths to try and lighten it? Just a note - my hair is still in excellent condition after a series of coconut oil soaks and snipping of a couple of split ends that had appeared. Not quite sure how it's managed it after what I've put it through, but it seems as though it would easily stand up to another bleach bath or two.

Thank you!