Overnight the modem re synced but back to the SNR of 5 it was on before the power cuts that effected it. It’s now downloading at 60 and 19/20 up. It might increases the sync speed more as that’s now at 63 but at the best was nearly 70

One little piece of advice. If you are using a separate modem and router, if you power off the router NOT THE MODEM, the modem and cabinet will sporadically re-sync over time but without triggering DLM. It's not going to radically change things, but they should settle on the best stable speed you are likely to get..