Wingspan 10-13mm; UK flight time May-Oct outside but earlier/later if wintering indoors.
Monopis crocicapitella is very similar but has paler hindwings.
This relative of the common Clothes Moth doesn't usually have an English name (I have seen it referred to as the Yellow-back Clothes Moth).
The caterpillar of Monopis obviella eats organic debris including wool.
Many thanks to Katrina Stewart for permission to use her photos above of this moth (taken in March in UK).