Try adding some chilli sauce. Mixed with the olive oil and fish it's amazing. After experimenting with quite a lot of chilli sauce with mackerel/oil over a period of years, I really recommend "Encona West Indian Hot Pepper Sauce".
If the 'sunflower oil' etc versions of the mackerel are available it also mixes extremely well with those and they can be cheaper than the olive oil tins.
If the 'sunflower oil' etc versions of the mackerel are available it also mixes extremely well with those and they can be cheaper than the olive oil tins.