Great, how much are the “cheapy” screws from B&Q, are these the green coloured screws. I guess they would be ok as such for soft wood deck but never on a hardwood.
I use the Fastenmaster 50mm at 4.74 pence per screw or 63mm exterior wood screw CMDS-63-500 at 3.93 pence per screw, these are the super cheap pro screws on the market