"Concrete Cancer Seminar", "concrete cancer specialist." Seminar - run for your life and don't look back
. You are not talking about brain surgery, just steel reinforcement in your concrete rusting as a result of water getting to it (as in the case of balconies) or the chemicals leaching out of the magnesite indoors when wet and penetrating the concrete to the steel and causing rusting.
Any half decent builder, handyman or anyone who has had previous experience can identify it. Getting it treated properly takes a bit more research to get the right person who will do it properly and with the right materials.
It is easy to identify or test when the magnesite is removed, or in bad cases when the magnesite is still in place and lifting. Testing the concrete is as easy as dragging a hammer over the surface listening for any drummy concrete - try an area where you know concrete or tiles are loose and you will get an idea of the sound. It is hard to tell though if a problem is in early stages of developing and is not causing drumminess, but no one will. In 5-10 years time it may become apparent then. But removing magnesite will lessen the risk of future problems, and if no flooding in your unit in last 10 years you are looking pretty safe.
Cancer is a name given to it by some people because of the way it spreads, and used by those like seminar presenters who want to scare you, but the correct name for it is concrete spalling .......... not so scary is it. If you look at all the balconies in your street you are bound to find several with spalling on the edge. And admittedly in "severe cases" people have to move out of the units while the floors in the whole building are repaired, but some of these are a result of problems stemming back from the balcony or where the building was not built properly in the first place and has nothing to do with magnesite.
P.S. There are many dodgy specialist companies who do poor work - including those who have been around for a long time which would make you think they must do a good job to stay in business, i.e. one that we used on this basis ...think of the letters SBR which I have jumbled and S representing a large capital city
P.P.S. When getting quotes, make sure you compare the quantity of material they are quoting on and the additional charge per lineal meter. Some quote on minimal work which at first glance looks cheap but their additional charge for work not included in quote can be very expensive. No one can quote accurately on work required, only a good guesstimate because the full extent is not known until work is started and the reo is chased back to clean steel.