Our DD (and every other baby born in our wider family in the last 30 years) is considered high risk for SIDS. Every baby born in the last 28 years has been monitored and taken part in research to inform the guidelines.
We follow them to the letter. They are there as a result of research undertaken on babies who have died, and the siblings/relatives of those children born later including my DD, her cousins, her aunts and uncles. These babies are monitored, on special equipment, supported by health professionals.
Piglett " It's not something that is encouraged widely by health professionals but my dd's doctor after seeing her case has a conpletly different opinion about t them now" - this isn't actually the case. My DD had a monitor issued by FSID, supported by my GP, HV, Paediatrician and Paeds Nurse. Her monitor was a combination monitor - apnoea/heart rate/sats. Any deviation on any of these things can indicate a problem. All babies born in our family are high risk and they are all given monitors (which are the same as the ones they use in hospitals).
Guidelines say that babies should sleep in the same room as their parents until they are six months - both at night and in the day. This is because the research has shown that more babies die from SIDS whilst sleeping in a room on their own than those that sleep in the same room as their parents until they are six months.
The reasons why don't really matter, it makes a difference, but there are a couple of research based theories as to why this is the case and the most supported is that the noise the parents make whilst asleep (at night) or pottering around in the day stops a baby falling into too deep a sleep where they "forget" to breathe. Breathing is a reflex, babies reflexes develop a lot over the first six months they don't always work as they should.
It is not known whether SIDS happens because babies stop breathing and their heart stops, or because their hearts stop and they stop breathing. It is known that being in the same room as the parents does reduce risk.
We had an all singing, all dancing NICU standard monitor that was attached to our DD with electrodes every time she slept until she was 10 months old. We didn't move her out of our room even though we had £1000's of pounds worth of equipment to alert us to any change in our DD.
She also has an Angelcare monitor - it's brilliant. But no monitor is good enough for me to have moved her out of our room before six months.