Those of you are in the path, or near the path, take a bit of advice from someone who has been there, done that.
Fill containers with drinking water.
Cook meals that can be eaten at room temperature and put them in a cooler or sealed container.
Put clean and dry clothing in large plastic bags.
No matter how much they complain, put pets in crates or carriers.
Gas up the vehicle in case you have to evacuate.
Any important papers, like insurance policies, passports, etc. should be put in waterproof bags and placed where you can get to them quickly, in case of evacuation.
I do so sincerely hope you don't have to do any of the above, and that all in the UK are safe.