I'm sorry, I'm not familiar with the abbreviation "NSW," where is that exactly? The one thing I wanted to make sure to let you know is that, looking at the meds you said you've tried, it doesn't look like they've tried you on many of the first-line treatments for POTS. Have you ever taken Midodrine? Florinef (fludrocortisone)? Mestinon?
Calcium channel blockers (like verapamil) aren't usually the go-to treatment for POTS. The other two medications you mentioned are beta blockers. Those *are* first-line treatments for POTS, but even so, they don't work for everyone. If your doctor isn't very familiar with treating dysautonomia, I agree that you need to be on the hunt for a specialist who can help you. The two speciailties that typically treat POTS are EP cardiologists and neuromuscular docs.
Managing any type of dysautonomia while parenting small children is tough! Is there any way you could get some help? Ask your doctor about having an aide in your home, as this is something that is sometimes covered by medical insurance. If not, then focus on ways you can manipulate your environment to reduce symptoms. Use gates/doors to keep the children "corralled" into one room so you're not having to chase all over the house or up and down stairs. Have someone help you prepare meals ahead of time and freeze them, if cooking is hard for you. Crock pots and steamers are also very POTS-friendly as you can just cut everything up, drop it in, and it will magically be a meal in a number of hours.
Have you tried compression hosiery? That's another thing that can help reduce symptoms, especially when you need to be upright a lot during the day.