We suggest planting in a double staggered row: 4 plants to the metre. To make a hedge stock-proof, your mix should include at least 50% thorn; Crataegus monogyna (Hawthorn) and/or Prunus spinosa (Blackthorn). A common mix includes: Acer campestre (Field maple); Cornus sanguinea (Common dogwood); Corylus avellana (Hazel); Euonymus europaeus (Spindle); Ilex aquifolium (Holly); Ligustrum vulgare (Native wild privet); Malus sylvestris (Crab apple); Rhamnus cathartica (Common buckthorn); Rosa canina (Dog rose); Salix caprea (Pussy willow); Viburnum lantana (Wayfairing tree) and Viburnum opulus (Guelder rose). You could consider Fagus sylvatica (Beech,) Carpinus betulus (Hornbeam,) Quercus (Oak,) and Tilia (Lime).