Hi and thanks for the question.
I’m assuming that when you say “fitted flush to the ceiling” you mean surface mounted rather than recessed into the ceiling. If that is the case I can give you some more information about surface mounted fittings that can be used in bathrooms. You might already have seen it but if not, this post on our site outlines bathroom regulations relating to lighting. One of the important things to understand are the different zones. Read the regulations for more detail but essentially the closer fittings are to water sources or the likelihood of being splashed or submerged, the higher their degree of Ingress Protection (IP) needs to be. Light fittings all have an IP rating.
Our Air range of surface mounted spotlights contains fittings rated IP54 as standard with IP65 available as an option. IP65 rated fittings are suitable for use in Wet Zone 1. That means they would be suitable for us on a bathroom ceiling in most circumstances. You should check the regulations and measurements against your particular circumstance but these fittings would most likely be suitable.
If this isn’t what you meant by the question, please let us know and we’ll try to help.