Thanks for the extra information – it certainly helps.
Your gas heating will not remove moisture from the air. Without going into the technical details, just warming air, without changing the amount of moisture present, does decrease the relative humidity. However, given the figures you quoted for outside R.H. and the nature of your enclosure, I strongly suspect that your hygrometer is not accurate. It needs to be checked to determine this. This is something you can do yourself or you can return it to the store and get them to do it.
If you do wish to check it yourself, the instructions are available on the net, such as in wikiHow. It is quite simple to do and only requires a common stuff you’ll have in the house. As this test is very accurate, it can be used to recalibrate your hydrometer if that’s all that is wrong with it. Even before you do that, if want a quick rough idea, use your hygrometer to measure the RH in the house. Then place it outside in an open but sheltered spot, and compare what it reads with the current Bureau of Meteorology (BOM) reading for your town - just google BOM plus your town name and select “Latest Weather Observations”.
You said you moved the water bowl to the warm end. My wording was to move it towards the warm end. I would not recommend going more than half-way for any extended time. This is also more of ‘quick fix’ while you follow up one or more of the other options, such as until you can purchase a larger water bowl. By the way, the water bowl should be big enough for the snake soak its entire body in without spilling water over the edge.
Using a heat mat you won’t have a basking / hot spot. So apologise if I confused you with that. There also seems to be a bit miscommunication going on about heating. To try and overcome that I’ll go through it from the basics, if that’s OK.
The preferred body temperature (PBT) for Childrens is usually quoted at 30 degrees or close to it. The idea is that thermal gradient should start at a few degrees above PBT and go down as low as practical. This then allows the snake to heat itself to a few degrees above PBT, as it would in nature, as it will lose heat once it is off and hunting. This also allows a hide to be placed at PBT, where the snake can remain for extended periods in comfort, be it to digest or just for security.
The notion of placing a hide partially on partially off the heating area is misguided. Put a a hide fully on the heating area by all means and the snake can warm up while feeling secure. It should then be able to move somewhere else at the desired temperature and feel secure without having to shuttle continuously back and forth, balancing heating against security.
With pythons it is recommended to maintain the day time heating regime 24/7 for approximately the first 12 months. After that, night time heating can be reduced or dispensed with entirely, depending. A maximum drop of about 5 degree in the overall temperature gradient at night is OK. Given Childrens are of tropical origin the cool end should not consistently drop below about 20 degrees during the winter months, otherwise you need supplemental heating at night.
Please lets us know how you go with the hygrometer.