I have bought batteries through aliexpress years ago, large white plastic case sh t it was too,  never again, I still see others buying from there and getting screwed over by some bad Sellers, Its not worth the risk for this stuff.    
Find a reliable source, preferably local.
Now Thats out the way...

So I got some batteries from https://www.bigweibattery.com.au/products/lithium-iron-lifepo4-battery-cells/ and they seem to be good so far, reason for choosing them, they where local and I could go into the shop and have a look and have a chat.
At the time they were the only supplier of that GFB  brand of battery (that I could find back then) and it looked like they got the batteries direct from the GFB factory, so had a better chance of it being genuine.

They have other Gel batteries as well and have some stuff on Ebay store.

Tried the twin core cable and its not bad https://www.bigweibattery.com.au/cables-connectors/It looks a little like the Jaycar stuff I bought years ago, but NO its not the same, it has larger strands and not as flexible, but works well for the price.

https://lifepo4.com.au/ is also a local supplier at Harvey Bay, worth looking at the range available and some information as well.

There are a few Ebay suppliers of this stuff, may be closer to where you live (in another state) and or a local shop that you could go in and have a look at what you can buy.

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Cheers Aaron
Off The Grid