The solar panels themselves can have no impact on the power supply at your house. But it's possible that something has been done by the installer that is! You should have the sparky who did the installer come back. What is it you reckon the power supply is doing anyway? What does 'sensitive' mean? They are not obliged to inspect tiles before installing - they are entitled to assume you do not have a leaky roof. But if that was so and the roof is now leaking then the installer should be fixing! You need the installer back!
Advice from me on this forum is general and for guidance based on information given by the member posing the question. Not to be used in place of professional advice from people appropriately qualified in the relevant field. All structural work must be approved and constructed to the BCA or other relevant standards by suitably licensed persons. The person doing the work and reading my advice accepts responsibility for ensuring the work done accords with the applicable law.