I really rate the Lee Stafford "Bleach blonde" or is it "beach blonde"? range including the "Hot shots". Look in boots. Lovely purple shampoos and conditioners that really whiten up hair that's looking a bit yellow or brassy
There is a shampoo called Touch of Silver which I used once after a highlighting disaster! It's meant for grey hair but neutralises the warmer tones and was v reasonable. They don't always have it in Boots but local chemists are usually a safe bet.
I rate both the touch of silver and the beach blondes really good stuff
But the best one is the john fredia colour glaze one. It's in a plastic packet not a shampoo or conditioner. That works the best, but it does glow with uv lights on your skin, which I found out with very odd patches over my face, arms and shoulders out clubbing. Not such a great look!
If your hair is real wreck (like mine! Too much blonde) use tigi urban antidotes, level 3 the red one, its the only thing I've found that stops my hair from breaking. I couldn't grow my hair for years it was always at jaw length, for 3 years I tried to grow it with no secces. Now it's around 5 inches below my shoulders in around 5 months and i don't it every wash.
I get it from eBay for 10 for both the shampoo and conditioner. Or tk max when they get it in