D4 Offside Wing Mirror

Hi, does anybody know if there is anyway of increasing the folding resistance on a D 4 (2013) wing mirror. With towing mirrors attached, to often the offside one "folds back", I have to put a bungy chord from mirror to the air intake grill to avoid constantly lowering the window to push it back.
The resistance seems quite weak compared to the near side.

Any help would be greatly appreciated, I hate the holdback chord but, also the idea of replacing it.
Regards Mick

I would hazrad a guess its just old, the mirrors are pretty pricey, my D3 n/s one with powerfold was 320 quid, bungee is the way to go.

Thanks for replying, I suppose that could be the straight forward answer. It crossed my mind to try a thin string loop pulled into the joint between the fixed & moving section, might just act as a friction "disc" .
Regards Mick