With the closure of Plusnet Business and Plusnet allowing customers to move to a residential contract, will the residential contract terms and conditions be changed - i.e.: Section 2 list how you must use the service:
2.1.3. use the services for personal use in the UK (so don't use the services to run your own business, but a couple of work emails or occasional home working are okay) and in accordance with our Acceptable Use Policy
(bold italic is my highlighting) So it explicitly disallows any significant business use - not much good for business use then!