Rooms to let

Today my new shelving arrived for the pantry, while I waited for the delivery, I emptied and cleaned the pantry - and got a rid of a lot of stuff - and sorted things that should be stored in the garage or shed (not the pantry).
The delivery arrived about lunchtime, by the time I assembled the shelves and got the things put away it was dark.
Hubby was up the village helping a friend who is ill.
I had to look around the garden this evening for something to Blip, snowdrops or primula, then I noticed this bug hotel and wondered "how can I tell if is occupied.