No, the AEBS is configured as DHCP and NAT - this was set up automatically
Correct, that would be the default configuration for the AEBS.
Unless this is your networking design goal, the AEBS should be reconfigured as a bridge. This will allow the upstream router that it is connected to to provide both the NAT & DHCP services so that network clients connected to any of the routers will be on the same network subnet. When two or more routers connected in series have NAT eanbled, you will have what is known as a "double-NAT" condition. This is not necessarily bad in itself but does cause other complications.