I use tinned Hamlyns Pin Head Oatmeal for breakfast Cereal as well as for other recipes such as my home made Wall nut and Cherry Energy/Protein Bars.

http://www.hamlynsoats.co.uk/shop/

I also like Scotts Porridge Old Fashioned oats.

http://www.scottsporage.co.uk/home.php

Both are local producers

I also like the 'Simply Sumptuous Special Muesli Luxury Fruit' 750 grams from the local discount supermarket Lidls. Storage life is improved by vacuum sealing and then put in a sealed mylar bag (2 bags at a time)