I assume you mean that you've been allocated a dynamic IP on your Plusnet connection.
It's not possible to change the PTR (rDNS) record for a dynamic IP. If you need a PTR record to your domain, then you need to request a static IP from Plusnet for which there's a one-off charge of £5. You then create an A record on your domain pointing to the static IP and then you can request the PTR record be changed to you domain.
Hope that helps
Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.
