Alko is actually a trailer hitch, and the hitch is also a stabiliser, alko used to say don't use swan necks due to the flex and loads the stabiliser adds to the bar. How ever things have changed a bit.
http://www.pfjones.co.uk/tow-bar-types-explained.html
That's providing its a big lever on the caravan that u push down to clamp the hitch to the ball. If its old style like a leaf spring you can also buy adapters for swan necks now.
The bypass relay is not needed for your model Dan. You would only need it if you car has bulb monitoring, can network on the lamps or pwm (pulse width monitoring) which controls the brightness of the lamps.
Most modern new cars will adapt stability parking sensors etc when they know its got a tow bar, and ford for one will void warranty if the corect electrics are not fitted and the car programed to adapt.and insurance companies are also backing out of claims if tow bar electrics that don't meet manufactures specs.
But non of that applicable to you, tow bars are now part of the mot in both security and function.
I'd still recommend a 13 pin socket and plug for the van.last thing you want is dicky lights.
http://www.caravantalk.co.uk/communi...a-13-pin-plug/