Certainly. Here's your translation into British English, following your guidelines and using your word list:

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Origin
Buddleja davidii 'Butterfly Candy Little Cerise' belongs to the family Scrophulariaceae. The species Buddleja davidii originates from China. 'Butterfly Candy Little Cerise' is a cultivated variety developed for its compact growth and striking flowers. This cultivar was selected for use in both gardens and public green spaces.

Characteristics
Buddleja davidii 'Butterfly Candy Little Cerise' is a compact, deciduous shrub. The plant reaches a height of approximately 80 to 100 centimetres. It is notable for its bright pink to cerise-red flower spikes that appear from July to September. The leaves are narrow, lance-shaped and dark green in colour. The flowers are rich in nectar and attract many insects, including butterflies.

Care
Buddleja davidii 'Butterfly Candy Little Cerise' grows best in a sunny location. The plant has few requirements regarding soil, as long as it is well-drained. Regular pruning in early spring encourages flowering and maintains the shape of the shrub. The shrub is hardy under European climate conditions. Watering is only necessary during prolonged dry periods.