can anyone advise on how to bleech knots on the piece? is this something that i could do or is it something which needs to be done by a pro? thanks for any help

It can be done at home using commercial hair bleach powder and developer.... but the danger is you will allow the bleach to seep through and you will end up with weird looking blonde roots, or you will overbleach and damage the hair which will cause massive shedding shortly after you do the job. Debbie has a kit you can buy as an alternative. Not sure what the advanatages of her stuff are.

so what is the exact name of the commercial hair bleach powder and developer?