Are towing mirrors mandatory

I understand where the cameras are but it still leaves the question of whether you can see far enough behind you with them or whether you need extended mirrors.

So i got my other half to take a pic of the screen that displays the camera images, i was going round a very gradual bend that can be seen at the time

You cannot see the rear corners of the van as per the illustration so you need towing mirrors.

Legal and sensible are two different things. 

Even if you can legally see everything with the cars basic fittings I would still suggest fitting towing extension mirrors for one really big reason. The police are more likely to stop a car towing a caravan if the car does not have the extension mirrors. And that creates an opening for anything else to be looked at too.

Plus you can then adjust your cars mirrors to see other things not covered normally and have an even safer rear view.

Let's consider a slightly bigger picture (no pun intended).  Would towing cameras replacing towing mirrors be adequate?  And if so would that be the case on a vehicle that did not have factory fitted cameras to begin with?

I hope the cameras producing the image illustrated above are just badly adjusted as they could not be used to show by how much the caravan was missing objects when passing through a narrow space.

A typical caravan (say Swift) is 2230 mm wide, and the Jaguar XE is 2075mm wide including mirrors. This makes rear vision, using integral camera lenses or the mirrors, legally impossible.

By the way, had it been a Range Rover at 2209mm wide across the mirrors, it would still be impossible. I don't know of any UK passenger cars wide enough.

Unless you tow a micro caravan with a Hummer, then yes, plus they also act like cat's whiskers - if the mirror fir, so does the van. 

Getting on to cameras as replacements, they would equally need to be on stalks( perhaps adjustable to suit width of outfit). Downside would be that clouting one would be even more expensive than towing mirrors.