will be using that once or twice in month
Based on your usage 110 bar is good enough for you but don't go below this. You can choose 120 bar if your budget allows. After deciding the pressure you would like to buy, choose the one whose flow is greater.
For example if you look 110bar category of well known brands like Karcher, Black+Decker, Bosch, I would choose Black+Decker 1400w only because it has more flow than Karcher K2 and Bosch Easy Aquatak 110.
Here are the flow rates of each of them
B+D - 6.5 l/m
Bosch - 5.5 l/m
Karcher - 6 l/m
If you want to go for Chinese ones, choose using the same technique I showed you. Here you need to do some research yourself because I can't remember specs of every Chinese pressure washer available.
Hope this helps you brother.