I've been making this for my family for over 30 years. Its been changed over the years and has evolved. This is a really tasty and filling dish that is cheap to make and the whole family will enjoy. Do try to include the ground cumin, it adds a depth of flavour that is subtle but brings out the taste of the other ingredients. This dish is great served with dumplings and it tastes great left until the next day and warmed through. Try substituting swede for the potatoes.
It looks like it is very complicated but it really is just a one pot meal. You can substitute fresh herbs just use a little more. Add the thyme at the beginning as it is a woody aromatic herb that does well with longer cooking, add the parsley and oregano towards the end of the cooking time if using fresh herbs.
If you want to add dumplings then do so after adding the corned beef and cook for a further 20 minutes.