Wow!! I feel for you BritKnee and wish I had a solution for you!
The worst we have in NE Ohio are black widows, and I've never seen one.
OK, your plight has caused me to search a little. Ortho makes a line of products called Home Defense MAX, and some of them kill scorpions.
You would need to be careful with them, and maybe only use them outside your home.
My brother swears by them for keeping spiders at bay. Some products can be sprayed indoors, but caution is needed. I've sprayed up high on walls to avoid a cat from walking on sprayed areas as one example.
I manage properties in Halifax, Nova Scotia, Canada. We don't have scorpions, but we have mice and minor insects. If you are renting, your landlord is liable to be found negligent should anything happen to you or your baby, IF you have informed him of the problem and he has not covered that access hole by the tub in a reasonable amount of time. Scorpions are pretty big and with the exoskeleton and claws I doubt they can fit through a 1/4 inch hole like a mouse can. There is no reason for them to be able to get into your home. We have trouble keeping mice out, but we wouldn't have a problem keeping scorpions out.