Preheat oven to 180°C. Grease and line sides of a 20cm x 11cm (top measurement) loaf tin with baking paper. Sift flour into a large bowl. Stir in caster sugar and poppy seeds.
Put honey, eggs, yoghurt, olive oil, lime juice and zest in a separate bowl and whisk until smooth. Add to flour mixture and whisk until smooth. Pour mixture into prepared tin.
Bake for 45-50 minutes or until a skewer inserted in centre comes out clean (cover with foil after 35-40 minutes to prevent overbrowning). Cool in tin for 15 minutes. Remove from tin and transfer to a wire rack to cool completely.
To make syrup, put sugar and water in a small saucepan and stir over a medium-high heat until sugar dissolves. Bring to the boil. Add lime slices and simmer for 4-5 minutes or until slices are soft and glossy. Remove lime using a fork and set aside.
Continue to boil syrup for 2-3 minutes or until thickened. Remove from heat and cool slightly. Pour syrup over cake and decorate cake with lime slices. Serve.