Panel has become unreliable and believe it is the panel not the wiring.  I have 12 proximity sensors, 12 smoke detectors and 2 heat detectors.  I also have 3 remote access keypads with simple LCD display.  I would like to add another 6 sensors.  My questions are:  Should I reuse the existing wiring? (its an old house and took a great deal of effort to fit professionally). Which system would provide the most intuitive fault finding?  Which system / manufacturer offers the most scope for the future? Can I reuse all the existing detectors? Would ideally like to be able to look in from a pc or iPad to see status?     Any comments or suggestions gratefully received.