If you are not currently offering bookkeeping services then you don't need MLR cover yet, it will be included in the ICB practice License, along with all the documentation etc.
If you are already offering services then contact the ICB as you do need a license now.
Just to use an analogy that a lot of people come across - if you open a new bank account, you will be asked to provide evidence of your name and address, which may be through driving licence, passsport, utility bill, etc... It is essentially the same thing.