Do I need a heat detector im my livingroom?

The IEE wiring regulations 17th Edition (BS7671) are not mandatory, so its not complusory to fit heat detectors based on these regulations alone. My guess is that due to the open fire and wood burning stove your electrical installer has done a quick fire risk assessment and is advising you that this would be a good idea due to the increased fire risk. He is probably basing this on the guidance in BS5839-6 which sets out the standards for fire detection and fire alarm systems. From what you describe your installer is recommending upgrading the system to category LD2, which is the minimum recommended for a small family house. It maybe worth checking with your house insurers as if you opt not to have the detectors installed and the wood burner or open fire is the cause of a house fire, you may not be covered so its worth checking first. Hope this helps. Please click on "like" if it does.

I agree completely with what electrical safety services posted , though both failed to mention that a CO2 detector would also be a safety precaution in this situation .

indeed it is - if your house is a 2 storey then the minimum requirement will be heat alarms in living room and kitchen along with smoke detectors in hall and landing - all interconnected and hard wired back to consumer unit with battery back up - as a further precaution i would recommend a heat alarm in dining room also