This is a new product review from the FSRH. Levosert is an LNG-IUS, which is the same as Mirena.
It seems to be as effective as Mirena and to have similar side-effects.
It is now licensed for 5 yrs of use for contraception (originally it was only licensed for 3 yrs of use).
It costs £66, so is cheaper than Mirena at £88.
Another disadvantage is that it is not licensed for endometrial protection with HRT.
Remember that Jaydess, another LNG-IUS, and Kyleena is also available.