Not a daft question at all:
moving day is hell BUT you'll get through it.
After exchange you have a financially guaranteed moving day (ie if it is missed there are financial penalties)so you can confirm booking with the removal company plan your exit and book a cleaner if you wish. Time between exchange and completion can be any thing from a couple of days to a few months but is usually about 2 weeks.
If you are packing yourself then this is when you will be doing it. If you don;t have DCs and have time you can clean gradually leaving only the tricky bits for the day itself. However i advise packing by the removal men...they are quicker and their insurance is good, compared to the moving costs it is cheap.
On moving day you movers will come early (or they may come the day before depending on how much stuff you have) all financial exchanges have to be complete in the chain by 4pm....your solicitor will aim for mid day but depending on length of chain and how good the other solicitors are this is a movable feast. Once your stuff is opacked and you have cleaned you may be sitting around or you may be fully occupied right up to the last second.
If you are moving far you lock up give estate agent or solicitor the keys and leave hoping against hope all goes smoothly and to time. If local you'll have more time and won;t have to pass them over before completion.
Whilst you have to give up your keys by the time stated in contract you don't have to move into your new place that day...you can pay for storage overnight in van and get in to property the following day if you want and can stay somewhere else.
If you are lucky the home you m ove into will be clean and empty...or it won't. If it is full of stuff you can apply for a financial penalty but the inconvenience is huge. You may cry! I certainly have.
My hoover goes with me in the car and is packed last and out very first thing.
I have 2 boxes in the car and overnight bags for everyone (including animals) which have all precious toys and sleep aids.
Box 1 cleaning cloths, sprays, bucket, bleach,loo cleaner, washing up liquid, bowl, washing up sponges dustpan, brush. Several loo rolls, one kitchen roll. Black bags.
Box 2 emergency rations, many many biscuits to keep removal men going, tea bags, milk in screw top, kettle, large bottle of water, meal for the evening in a casserole/pasta bake usuually frozen to bung in oven , sandwiches for the day, random food items that might be useful, mugs (enough for all) plates or cardboard plates, kitchen roll (yes again). Paracetamol and bruffen. I don;t drink but I think wine would also be a good thing!
HTH