Hitch locks

[Harrythecat]

I've fitted a towbar to our T5 and bought a Motolug trailer to two two motor bikes. Next week we'll be off on our first towing 'trip''. At times obviously the van and trailer will be left on site while we ride the bikes and security of the trailer in particular is a potential issue.

Does anyone have any advice on hitch locks as there seem to be a variety of products out there both in terms of cost and style?