My dad got an offer in advance of the price rise in June that allowed him to renew his contract (40/10) at £22.99 a month, I had renewed just the month before but the link in his email allowed me to renew it again at the new price (previously £26.98).
https://www.plus.net/campaigns/renewContract/DualPlay/UnlimitedFibre18/
https://www.plus.net/campaigns/renewContract/DualPlay/UnlimitedFibre18/