After some intense discussions between PUG and PlusNet, PlusNet have finally agreed to change business contracts to bring them in line with residential ones. The change being you automatically go onto a monthly rolling contract after the first 12 months, and it is also retrospective.
To be honest from the discussions on the usergroup forums they didn't have much choice. Neil Armstrong admitted that when they changed the T&Cs last year they didn't include the clauses which committed business users to annual rolling contracts.
As such PN would have a hard time enforcing annual rolling contracts - they only argument would be that given the ambiguity in the T&Cs anyone who signed up on the old T&Cs (but not under the new ones) could reasonably have expected the annual rolling contracts to continue. However given that some business customers explicitly queried the ambiguity and were told contracts went to monthly after the first year from PN CS (and this I believe is on public record in the forums), that somewhat weakens the case.
As such the only way for PN to enforce rolling annual contracts would have been to issue a new set of T&Cs correcting the ommission. However, this issue came to like (according to Neil's post) because they have more business customers leaving (due to the well discussed problems of late). As issuing a new set of T&Cs would require giving customers 14 days notice during which they would have the right to terminate the contract there and then, that probably would have caused a mass exodus under the circumstances!