Gaaah, yes that is a typo . The DNS server for the nodes is 172.27.41.2 (MAAS server) and the Proxy server is 41.2 as well. The gateway is 172.27.41.1 on the L3 switch.
I have seen examples where the MAAS server is the gateway for these other subnets and iptables is used to NAT internet access for the nodes. I didn’t do this and tried instead to use the inter-vlan routing on the L3 switch. Which generally works I think, but I have a feeling it is not best practice?
The machine hosting MAAS is 100% new install of Ubuntu Server 20.04 with the bare minimum installed, so definitely no other DNS, Proxy or DHCP running on it. MAAS installed via snap.