A planned 3 hour period without power is more manageable than an unplanned one.
Can still cook with a gas hob, but will have to light it with a lighter/matches. Or have dinner in the slow cooker in the morning, so it's ready probably as the power goes out. Or worst case, having a picnic style tea with sandwiches.
Flasks for hot water, or more likely...taking the opportunity to make proper hot chocolate in the milk pan "because the kettle is off"
Work wise, I'm fairly fortunate I realise, but I could go to the office if it falls in a different block - its 30/40 mins away. If its at the start/end of my work day - making up hours at the end/start. Or just making sure I have an offline document or two till the powers back.
The more reassuring thing would be to speak to your company about your own situation.
Having some power packs charged for phones.
Torches or some press on/off led light things
Blankets and jumpers and hot water bottle.
Changing the heating timer to warm up a little earlier or later if It's on a schedule, or bringing it up a little warmer so it doesn't get as cold.
Setting reminders not to put the washing on/dishwasher etc 30 mins before the power goes...
Getting milk out so I don't have to open the fridge.
Earplugs so I don't beat the house alarm off the wall as it reminds us CONSTANTLY its on its battery.
I'm not sure how big the blocks are or if multiple areas across the country form a block - but working out where the closest block is with power - and if you have somewhere within that area you can visit if you need.