On the carpet at the patio doors ther is a (small) trail of that silvery stuff that slugs leave behind. Outside the window on the patio there is a small amount.
The patio doors ahven't been opened since we had all that sun way back in May. There is no sign of the slug actually int he house and the trail isn't anywhere else. But how the hell has it got in?
Is there anything I can buy to stop it getting again