Thus all depends on what way you do the works! Also depends on the diversity of each of the circuits you are going to put in I.e what you intend to be in the garden room! You are on the right track of using an isolator switch and a separate consumer unit. Also make sure you go with the regs on size and correct cable type!
You need a registered electrician to come and look and advise you on the best way forward regards Shaune delta electrical
The installation method for your job will depend on loading to the new annex, I would recommend that a reputable electrician works out theocracy method for you. Kind regards
Nick shares his story of finding local tradespeople in his new area.
