Yeah that’s a no go mate, I couldn’t even do my job if I had a £100 phone it would end up being a cluster fuck as I need to constantly look at spreadsheets, and multiple email inboxes and work through a web Ui portal and none of that is gonna be a good experience on a phone at that price.
I’ve used enough of those cheap £100 phones be they new or second hand to know for someone who’s actually using their phone to do work they are completely unsuitable.