I chop my potatoes to roughly 2 cm chunks with my treasured vegetable chopper so the timings are for potatoes cut into that size, it will be longer if you have bigger chunks - obvs
Place the chunks into a large saucepan and cold water. Boil for 5 minutes from the time it starts to bubble.
Drain the potatoes and give them a little fluff and set aside.
Place the oil and the onion in your frying pan and set over a medium heat.
Cook until starting to brown, probably ten minutes.
Add the potatoes and butter
Fry until the edges are crispy, you may need to turn up the heat to make that happen.
Once the potatoes have some brown and crispy edges add the corned beef and worcestershire sauce. If there is a lot of excess oil in the pan carefully remove it so that about 1 tbsp is still left in there - difficult I know to tell but just guess Susan.
Fry the whole lot for another ten mins or so turning the mixture carefully with a flat fish slice so the beef doesn't break up too much.
You can top with a runny fried egg for the full on retro experience.