Thank you BorderPaul for the link and your observations.

It's for my daughter who is terminating Virgin as, with you, though it was fast it was unreliable (in Sydenham Hill). Moreover expensive and getting more expensive.

JGD - I doubt any of the 'value' ISPs will offer you a fixed IPv4 nowadays. They are getting expensive to aquire particulary for large ranges. You have to consider going to A&A or Zen who will charge you business rates but ae very reliable and can squeeze more out of a Openreach line than BT can ...

Perhaps BP can correct me but I think Community Fibre have got round the problem by not offering IPv4 at all but proxying everything via IPv6. Or do they do SLAAC IPv6 which basically fixed the IPv6 to your device's MAC?

If so you can possibly have many devices using Cloudflare or similar to deliver via IPv4 to folks who have yet to enter the IPv6 world. This works from my Zen /64 allocation.

Stuart (from part of Sydenham currently beyond the reach of CF or 5G).