Got it, and I think this applies to a great many that have had hotel wifi issues:
The particular provider for this hotel used a simple trick to try and prevent travel routers, their captive portal auth page is sent with a TTL of 1.
Added this to the custom firewall option:
iptables -t mangle -I POSTROUTING 1 -j TTL --ttl-set 65
iptables -t mangle -I PREROUTING 1 -j TTL --ttl-set 65
First line I don’t think is necessary but is taken from another blog, and the second line I had to google for as I didn’t really need the outgoing to have a higher TTL but the incoming.