Thinly slice aubergines lengthways and lay on a greased baking tray. Drizzle with balsamic vinegar and season with salt. Bake at 400C for 3 mins, allow to cool then use to line an oblong mould. Seal lamb and venison fillets in a hot pan, then roast for 3 mins. Remove from oven when the meat is still pink and moist. Allow to cool. Half and de-seed the peppers, brush with oil and grill to char the skins. Remove skins when cool and slice into strips. Slice courgettes and white part of leeks lengthways and roast in same way as aubergines. Put all remaining ingredients into a saucepan, bring to the boil then simmer for 5 mins to reduce liquid. Pass through a strainer. Layer mould, starting with venison, peppers then lamb, leeks and Courgettes, pressing each layer down firmly. Slowly pour reduction into the mould to cover. Clingfilm and place a heavy weight on top - refrigerate until well chilled. Approx. 2 hours. Carefully unwrap terrine, turn out and slice to serve.