First, none written rule, tests in the Lab (garage, room, etc) don't deploy until it works
Second, no info. Difficult to understand your scenario
Third, it's not easy to set this devices, they are not plug & play
Please answer this questions
What did you set, Test Mode or a Country, In case a country which one
Are you sure IPs 252 and 253 are out of dhcp pool from your NBN router, if you are not, change it to 5 and 6
Strange Gateway, 10.0.0.138 are you sure that is the Gateway and not 10.0.0.1
Distance of the link
Please clarify this one, it's confusing.
1 xTP-Link CPE 210 setup as client connected via WiFi (to local 4 port WiFi Router (home2) with Survey working and locked
How is that a 210 Client is connected via wifi to a router
That 210 should be connected wirelessly to AP
And from there you connect that router via lan cable between 210 and router,
That router has to have a dif ip from 10.0.0.X should have like 192.168.0.1 or 192.168.1.1

I got it all working perfectly for 2 days but then the AP was turned off and it stopped working after they turned it back on the next day.

This was the setup which was working fine with this config over a 1km distance

Site1 (Shed)
NBN NTU (NBN Fixed Wireless).
Ethernet Cable connected to WiFi Router1 LAN Port
Telstra Wi-Fi Router1 (10.0.0.238 and DHCP server 10.0.0.1-10.0.0.50)
TP-Link CPE 210 (AP Mode, POE, Maxstream on, Distance 1km)
Ethernet Cable connected to WiFi Router1 LAN Port

Site2 (House)
TP-Link CPE 210 (Client Mode, Maxstream on, POE, Distance 1km)
Ethernet Cable connected to WiFi Router2 LAN Port
Telstra WiFi Router2 (10.0.0.251, Bridge Mode)

Any idea's why it stops working after the AP is turned off at night?
Do I need to leave it on 24hrs to keep the connection alive?
What if there is a power failure?