Looks like if you ring up Plusnet threatening to leave they will do a price match. I was looking at the landline deal with the Post Office at £12 per month (bit cheaper than Plusnet). I'll cancel my landline at the end of November when my 12 month payment expires. I'll then be looking to move my internet connection and I've been with them since 2002. I reckon I'll be saving around 126 quid a year on my phoneline. First 3 months free.
Price matching would be good and timely. Was with the Post Office phone and broadband for 4 years. They (at the time) leave you dangling on the same tariff and don't make any special offers to you. Even when I told them I was off to Plusnet. I don't know if they have updated the User Information panel of the website but it was like something out of the Internet Ark it was so limited for information or service details!