What next?

So, I'm trying to get my blonde streak at the front of my hair, which was dyed with permanent mahogany box dyes and various Adore reds and browns.

I faded lots first with lots of Head and Shoulders washes, then did a Colour B4 just on the one strand that I wanted to lighten, which took it to an ash/ gold light brown very similar to my natural colour.

Today I did a bleach bath, starting with the lengths and only applying it to my roots right at the end.

It's gone very brassy indeed, and took a lot more at the roots which went instantly light yellow. I'm gonna give it a rest for a little while to assess the condition but I'm wondering if people think I need to have another go at the Colour B4 rather than heading straight to another bleach bath when I do decide it's time to fix it?
Edited to add, I did another Colour B4 and bunged a bit of purple dye in my conditioner and it's already looking better! If I can face all the rinsing again I might do one last Colur B4 and then rest it before another bleach bath in a week or so!