You can but this is the guidance from the IVA manual;
“Side repeater indicators mounted on a "cycle wing" that move with steering movement, are required to meet the angles of visibility requirement with the steering in the straight ahead position only. Where fitted to a "Lotus Seven" style vehicle (having a proportionally
decreasing body width towards the front) a side repeater does not need to meet the angles of
visibility requirements providing it is clearly visible to other road users to the rear of the nearside and offside of the vehicle as appropriate.”