I've done an awful lot of council rewires in my time, what usually happens is about a week before the work starts the place will be visited by the tenant liaison officer and the senior electrical guy who should both be pretty clued up on what needs to be where. As has been said earlier, if you can get those loft boards up then do it. Some of the sparks really don't care and will smash their way through anything that's going to hold them up others will take the time to do things properly it pretty much depends on how much time they're given for the job and what if any bonus system is in place. If there's anything big and heavy in the way of switch drops or socket positions, move it. Roll up as much of the carpet as you can away from the walls. If there's any laminate flooring, take it up.
Best one we did for Gateshead Council, the tenant had hired a 40 foot shipping container and put every scrap of furniture in there in his garden except for his bed, kettle, microwave, TV and fridge and packed his wife and kids off to her mothers for a few days while we were in there.
Get lots and lots of dust sheets and cover everything, the dust from chasing will go everywhere. Anything of any value, either monetary or sentimental try to find a good home for it. Accidents do happen especially if the guys are trying to get it done quickly.
Hopefully all will go well but the tenant liaison people are there to guide you through the process so don't be scared to ask them anything.
