Mobile phones reparing with accessories - how good is this business in Warsaw, Poland?

hi all viewers, I have 5 years mobile repairing/unlocking experience and currently I am working in Scotland. In future I am interested to start mobile repairing shop in Warsaw and I want to get information about:-

1. How much is medium size shop rent in Warsaw city center.
2. Is mobile repairing/ Unlocking (sale and purchase) business good in Warsaw.
3. what kind of legal requirements to start this kind of business.

I have been lived about 3 years in Warsaw and know little Polish.
please help me to know better, is this business good or not in Warsaw and also guide what kind of business best if I want to start.........

thanks

Hi
In my opinion there are many mobile repair shops in Warsaw already and I don't think this kind of business will grow big.

Justyna Thanks for your reply opinion, can you please little help me more, how much is rent of normal shops in city centre warsawa like (8x12 or 6x12)???