Calder Steel Postboxes
A really popular robust tapered contemporary design. Top posting slot under lift up lid. Excellent weather resistancy and security as the lock is hidden from view. The front of the box is a much thicker grade of steel thatn other boxes at this price point and also has an extra wide posting slot.
Easily suitable for A4 size.
Also available in stainless steel in the "stainless steel post boxes " category