You can heat them up in a saucepan of simmering water.
You can fry them in a frying pan.
You can grill them until cooked through
You can cover in batter and deep fry.
You can even wrap in cling film and heat in the microwave for a couple of minutes.
Whichever way you decide I hope you will enjoy.
I'm not a fan of saveloy to be honest. It's just a ready-cooked well seasoned smoked pork sausage coloured red with food grade potassium nitrate (saltpetre)