Adrian,
This has nothing to do with sway control, but I'd advise you to check the
weight and tongue
weight of the
Scamp. I'd bet that your Class II hitch is overloaded. And when I say check the
weight, I mean on a scale, don't rely on the published figures.
I used a single friction sway control on my Class III hitch towing my
Casita. It worked very well. I don't think the brand matters much.