Heat 1 tbsp oil in a pan and gently fry the onion for 5 mins until soft. Add the garlic and cook for 1 min. Add the oats and fry for 2 mins more. Tip into a bowl and set aside to cool.
Add the rest of the ingredients to the cooled mixture and mix well with your hands. Season to taste and shape into 8 patties.
Heat oven to 200C/fan 180C/gas 6. Heat the remaining olive oil in a large, non-stick frying pan and sear the burgers on each side until well coloured (3-4 mins). Transfer to a baking sheet and cook in the oven for 10-15 mins. Serve in rolls with Tangy tomato chutney and cucumber slices.
For the chutney heat 1 tbsp of olive oil in a pan and add 1 finely chopped onion. Cook for 5 mins until softened. Stir in 1 crushed garlic clove and cook for a further min. Add 1 tbsp sundried tomato paste, a 400g can good-quality chopped tomatoes and a pinch of sugar. Gently cook for 20-25 mins until rich and thick. Season to taste, then leave to cool before serving.