I used olbas oil so i hope it is safe. I dont think it said anything on the package about it not being safe. I ahve taked baths in it before when I've had really bad colds but thought it may not be the best idea during pregnancy! Check with the pharmacy.
Olbas is fine.
I was advised that Sudafed was also fine, so if you get really bunged up you can take this.
There's actually no real reason not to take Lemsip as it's paracetamol based and psuedo-ephadrine, the decongestant, has no known ill-effects.