Do you still have the original HomeHub that was supplied with the modem to see what that can do?
It's always worthwhile keep the original equipment for times like this.
From a bit of googling it seems possible that a previous PPoE session may not have cleared down properly and therefore a new session could not be created , hence the Timeout issue. The solution to that problem was to reconnect the ISP's modem/router & that cleared the issue. Apparently it may clear automatically given a bit of time but that's not for certain.
I no longer have it, I have been with BT for 15 years in total at this abs my previous address and no longer have the old home hub as it was awful at the time so don’t have much of a choice. Looks like I will have to wait until the come on Sunday. Thanks all