You're Only Young Twice S02 E01 The Box Number

Cissie places an innocent advert in the paper, requesting somebody with whom she can swap crochet patterns, but the ambiguous wording attracts a mountain of unsavoury replies, leading Flora to believe her friend is in danger from a stalker. She sets a trap for him, and although his intentions are honourable, it gives Flora the idea of placing an ad of her own.