I am a landlord and my managing estate agent just recently organised an electrician to carry out EICR. Came back as unsatisfactory, no RCD protection on: lights, smoke alarm, door bell and immersion heater. There is RCD protection on sockets and cooker. Electrician suggests changing the board. Is there an alternative eg. Adding another RCD to the current board? I was also worried that putting in a new board could cause other faults in the house that would then need remedying. House is mid 1990s construction.