Yes you can as long as
1. You make sure there is enough room for guests to hang their clothes and store their belongings
2. You don't leave anything that is valuable/sentimental out
3. You have a clear space in your fridge/kitchen which guests use for food etc
Perhaps lock one room and keep personal items there.
Obviously in London you can only let out within the 90 day restriction and you need to make sure there are no restrictions in your block against STRs/using flat for commercial use
@Lina4956