I just got to the end of my 2-year deal with them so I rang up to see what they would offer me to stay.
I've been on £15/month plus linesaver at £185/year, giving a total of £30.40/month for Fibre Extra (I get the full 76/20 since 100m from cabinet).
The new offer was £12/m Fibre, £198/yr linesaver, a total of £28.50/m. Not too bad I thought, but I decided to survey the market before committing. Looks like there isn't too much else out there - £30/m is the lowest for new customers (including Plusnet).
I looked at the Pulse8 line rental (£13/m) but Plusnet want £21.50 for the Fibre if you don't take their line, so £33.50/m offers no advantage.
I'm inclined to sign back up with Plusnet. They've given me a pretty good service over the last three years.