I've categorised my shopping list into 3 sections and some healthy snacks:

Protein:

1.Peppered Smoked Mackerel

2.Salmon Fillets

3.Smoked Cod Fillets

4.Smoked Salmon

5.King Prawns (very low cals and high in protein)

6.Chicken Breast

7.Chick Peas (high in protein and fibre as well as several key vitamins and minerals)

8.Green Lentils (not only high in protein, but also in potassium and fiber)

9.Natural Yoghurt

10.Free Range Eggs

11.Cottage Cheese

12.Feta Cheese

Carbs:

1.Brown Rice

2.Whole Wheat Pasta

3.Quinoa (gluten free, high in magnesium, iron, potassium, some beneficial antioxidants)

4.Corn on the Cob (I consider this as carbs!)

Veg and fruit:

1.Lettuce

2.Cauliflower

3.Asparagus

4.Spinach

5.Watercress, Spinach and Rocket Salad

6.Mint (great in salads)

7.Flat Leaf Parsley 

8.Courgette

9.Bell Peppers

10.Radish (high in Potassium)

11.Mushrooms (low in carbs, high in potassium and minerals

12.Vine Tomatoes 

13.Beetroot (high in Vit C and Potassium)

14.Apples

15.Strawberries

16.Blueberries

17.Raspberries

18.Lemons

19.Avocado

Snacks:

1. Mixed nuts (healthy fats)

2. Rice cakes (great source of carbohydrate)

3. Low Cal Popcorn (carbohydrate)

4. Mixed Dried Fruit (carbohydrate)

5. Nature Valley Protein Peanut Bars (Protein & carbohydrate)