They are vine weevil, Otiorhynchus sulcatus, or a similar species (some of which are mentioned in mthe link below)
If you have pot plants that may be the source, but they wander around and could easily have come in through windows.
Brilliant, thank you for this.
Makes sense, got a couple of container plants inside and in particular, one money tree which has lost branches in the last few days.
Thanks again, will have into look at treating indoor plants!
Vine weevils love to feed on the roots of many pot plants, including money plant (Crassula). It is the larvae that do the real damage (though adults chew bits out of the edges of leaves). Take the plant outside, and over a tray of some sort, take it out of its pot. You may see the little white grubs immediately, or you may have to prise away the soil before they are exposed. It can be distressing to see how riddled with the blighters the soil is!
I used to pick the larvae and pupae out and put them on a steep-sided but shallow saucer for the robin to pick over. For safety, I'd put that suacer in a larger saucer full of water - forming a moat - just to ensure the larvae can't crawl away into the garden.
Sedums, sempervivums, and other outdoor succulents are particularly at risk. The larvae will chew their way up the inside of the stems until they reach the point where they are the same width as the stems. At that point the stems become detached and may start to die. But, because they are succulent, they can survive (not thrive) without roots for quite some while - which can lead to the plant as a whole looking OK, just lacking in vigour. Eventually, you'd go and investigate, and only then would you discover it was just resting on the soild in pieces! And by then some of the larvae would have moved on to other plants!
Pot plants are especially at risk if you put them out on a terrace for the summer. The wandering adults find them and lay their eggs in them. You wouldn't notice until months later.
There are chemical and biological controls.
Many thanks again.
I am dreading taking them out of the pots now! Think I will do it tomorrow...
It is all starting to make sense, I have got three plants in total and I left my largest money tree (about 6-7 years old) in the garden last summer, that may have been where I picked the weevils up. There are a few holes in the centre of some leaves on this one, and whilst it is a different plant which is falling to bits, I am worried for the largest one now!
I will get some treatment products tomorrow and hopefully sort it out.
Thanks again for the info!