Although low output MC carts are (mostly) pretty expensive, so unless you are spending more than £200ish on it it's probably going to be MM or high output MC which will work in a MM stage.
If you did want to use the phono stage with a low output MC cart you could use a step up transformer in between. But again they tend not to be cheap so you would probably be better off buying a separate phono stage that has enough gain for the cart (and bypassing the built in stage)
Although low output MC carts are (mostly) pretty expensive, so unless you are spending more than £200ish on it it's probably going to be MM or high output MC which will work in a MM stage.
If you did want to use the phono stage with a low output MC cart you could use a step up transformer in between. But again they tend not to be cheap so you would probably be better off buying a separate phono stage that has enough gain for the cart (and bypassing the built in stage)