Electrical engineer wanted - residential house electrical related issues

Hi, We just moved in a house in eastern Sydney and found several electrical related issues. Tried some electricians but seems they don't have sufficient knowledge or equipment to completely solve the problem. Issues we faced are: - High frequency electricity noise in the house, not sure where it's from. Probably need an oscilloscope to detect and locate the source. - Buzzing noise at the power points when they are connected and turned on -Flickering and buzzing LED lights after 10PM caused by 750Hz ripple control signal. Please get in touch if you have the related knowledge and equipment to help with the above.