Possible 15 minute disruption to Dawsonera ebook access on Sunday 13th May

We have been informed by Dawsonera, one of our ebook suppliers, that there may be a 15 minute disruption to access on Sunday 13th May between 2pm and 4pm. It is due to external maintenance being carried out by BT and have not been able to be more specific about the exact timing of the short disruption: