I have a Nissan Qashqi and the wing mirrors are quite large I tow a Pennine Sterling folding camper and getva good veiw from my mirrors.
But is it against the law to tow without towing mirrors.
You can buy small stick on mirrors from Halfords which fix to the inner side of wing mirrors, I can't remember what they are called. But they very useful, once fixed you just adjust independently of the wing mirror.
The law is not that towing mirrors must be fitted, the law requires a certain field of vision to be achieved behind trailer. The easy 'rule of thumb' that can be applied is that if trailer body is wider than car body, then towing mirrors are required to achieve that field of vision.
If it is a caravan or trailer with high load if wider than car body then mirrors definitely required but perhaps arguable with a lower trailer? Even so with low trailer they might still be required, I would have thought?
If you can see over the top of the trailer you do not need extension mirrors. If you cannot and the trailer is wider than the car then you must be able to see what is described on this website http://www.caravanwise.co.uk/caravan-tips/towing-mirrors.html
------------- Bill
For a licence dated 1997 or later you must add together the plated max weight of the caravan and trailer, if the total is 3500 or less you can tow it. You may even tow a caravan with a MAM greater than the cars unladen mass the restriction was removed in 2013