OK, this is a bit embarrassing ... But I've fixed this.
I'd previously defined alternative DNS servers for our laptops to bypass our slow ISP's DNS servers. I removed the list of DNS servers and now I can see the PirateBox in Safari.
I'd previously defined alternative DNS servers for our laptops to bypass our slow ISP's DNS servers. I removed the list of DNS servers and now I can see the PirateBox in Safari.