As far as I am aware, a 0w30 and 5w30 will have the same viscosity at working temps.
At very cold start up the 0w30 will flow better than 5w30.
But you only see this advantage at below freezing temperatures so some would say the price premium may not be necessary as UK winters rarely hit such lows.
I can't imagine any adverse difference, only positive ones where temps are below freezing