Hi @Punky_pj,
In the experience of Roon forum users, Hyperoptic appears to have implemented blanket carrier-grade network address translation (CG-NAT).
The good news is, many users have been able to circumvent Hyperoptic’s CG-NAT by requesting a dedicated external IPv4 address or static IPv4 address from Hyperoptic. If that’s not available, you can ask to be switched to IPv6 if offered.
Unfortunately, I think these services cost around an extra £5 monthly 
.
CG-NAT doesn’t rule out the possibility that the management has an enterprise router somewhere, so I’d first ask the building if they’ve installed a central hub for Hyperoptic on site.
We’re here to support you. I recommend taking a glance at this thread: Attention: Hyperoptic UK Uses IPv6 and CG-NAT [Solved - Request Static IP] - #73 by Michael_Harris