Another internal feeding larva that can be found overwinter is Metzneria aestivella.
Look inside the seed heads of Carline Thistle: I’d recommend wearing gloves! The presence of larva is often betrayed by a slight ‘untidy’ look to the seed head. There’s usually multiple larvae present.
I’ve recorded these from several sites across East Kent, from Folkestone Warren to Fowlmead CP; finding them particularly abundant at the latter site.