Aquarium In Cold Room

Hi, not sure if this is right area to post, if not please feel free to move post.

I have a 250l fluval aquarium with 300w heater, which has 8 scissortails & 2 tiger barbs in it, temp normally sits between 25-25.5C. Due to having new windows fitted, the room tank is in will be without heating for several hours & the forecasted temperature is about 1-2C. My question is:- Can I leave tank the way it is, or am I better wrapping it in newspaper or a blanket?

Thanks Sue for the advice, sorry for not replying earlier, been busy with getting ready for new windows   
It's now 2 days since windows were fitted & fish seem OK, I wrapped tank in bubble wrap & window fitters were great, they managed to replace window in room with tank faster than I expected, so no drop in temperature, also weather was milder than forecast 
Thanks again Sue for your great advice.