Testing asbestos under a skimmed ceiling

Hi

We are moving into a new property this week. There are no fire alarms installed so we are going to have to drill into the ceiling a few times.

The house was built around 1994 (UK). The house next door and all houses on this estate seem to have or have had textured ceilings.

Our new property has flat ceiling so assume it has been skimmed over at some point.

We have someone coming to test for asbestos this week

My question is, is testing once it's skimmed over reliable? How do they know where the textured coating was?

I wouldn't even bother if I didn't have to install 3 alarms and am really paranoid about disturbing anything!