Hair colour advise needed - fed up with my colourist

[Bracky]

Okay so my hair at the moment is highlighted blonde and bobbed and in the best condition that it has been for years as I took a rest from colour for a while. I've been going to a new hairdresser and each time I go I tell her that I would like it as blonde as possible. Each time I leave with another head of highlights, in the same colour as I came in. I feel like banging my head against a brick wall. I used to be platinum blonde when I was a teenager up until I was 20. I went dark for a period but never felt like myself, since then it seems to be impossible to get back to the colour I had. I don't even like highlights on me. I hate that I still have root showing. I hate finding the odd dark slice of hair. When I said I wanted it blonder she sucked air through her teeth and said 'it will be too blonde'. Surely that's a matter of personal taste?! I guess I'm looking for advice on what to do or say or somewhere to go to get the results I'm after. I've tried several hairdressers. I've paid over £200 for a colour at a famous international hairdressers which shall remain nameless and still come out with a set of flipping highlights :grr:

My hair is naturally a dark ash blonde (not the darkest on the scale but not quite medium blonde). Please help. It's getting to the stage where I'm considering buying the Wella highlighting kit and whapping the stuff all over my hair myself

Edited to add - the pic in my avater was taken when I was in the middle of my colour correction - from brown to my natural colour a good while back.