Speed drop - possible cause

[#1]

I was out yesterday afternoon and didn't go online, on my way back I noticed two openreach vans at the local cabinet.
I powered everything down overnight because of an intense electric storm overhead.
On turning the router back on it started connecting at 256k, it's up to about 312k (after 10 hours) its normally  around 2mb.  
How long should I leave it before logging a call? Could openreach have 'applied' a change?

[#2]

Sync rate is showing at 160k on BTs side, not sure if your router is reporting the same?
I'd guess it's down to either the BT work or the lightning (or maybe even both), either way our faults team will get it sorted for you.