Help! Storage heater quote/repair

Both my storage heaters wiring trip 2 days ago at the same time. We contacted the electrician who quoted $700 to change the control board, change the 2 heater switches and re-do wiring for both heaters. He said heaters look okay and need not change. No hacking but he will do the HDB flat wire casing from switch to the false ceiling.  Ours is condo and all wiring to date is concealed wiring.

One of the heaters is about 10 years old and other is 6 years? No leakage. Both working fine to date. Problem was the heater indicator switch has been spoilt for a year or so and sometimes I suspect the heater is on for whole day. Would this cause the trip?

Is $700 a reasonable fee for some wiring works only? I am a newbie at reno works and would appreciate some feedback. Thanks!

I was thinking may as well change one of the heaters but how much will the installation charges be? I note a lot of forummers quoting $100 to $200 for installation - other than the piping works, would this include the wiring work to instal the heater switch etc? Ours is a condo and has concealed wiring.