I have had IP ranges with plusnet that I've probably had for well over 15 years now. I've had no issues with them. Setting up the routers I've had supplied by plusnet over the years hasn't been a problem. I've just had to give the LAN the first IP in the range, then set the subnet to 255.255.255.248 and disable NAT and DHCP.
I've now upgraded the first of my lines to fibre, and I've been sent the HUB One as replacement. I can't for the life of me find where I can disable NAT. I suspect that this router doesnt support anything other than NAT and would just like some confirmation of it. I tried asking plusnet, but rather helpfully they no longer offer support for router config.