There's no need to buy a regulator from
Scamp, because they are common items carried by every RV parts store... but I see no problem with getting it from them if you want.
I don't think
Manchester makes regulators - perhaps Scamp gets theirs from Manchester along with their propane tanks, but the dual regulator looks like a Marshall model 254... although I don't recognize the single-input regulator.
The orientation of a propane regulator is determined by the vent, which should point down. It looks like the vent in
Scamp's parts store photo is facing left and a bit toward the camera, which means that this regulator should mount so the hose runs into it horizontally, turned to face that vent down which would put the mounting plate (under it it the photo) vertically against some support.
Usually, there is a plastic cover over the vent, especially if it is used outside (rather than in a compartment with the tank, as is normal on motorhomes and fifth-wheel trailers).
Any reasonably sized single-input regulator can mount directly to the tank. The Scamp single regulator comes with a hose for the tank connection, but that could be removed and a fitting for the tank valve screwed directly into the regulator (assuming the regulator has the usual pipe threaded port). My motorhome, for instance, is done this way. I would rather use a hose as Scamp intends and support the regulator solidly on a fixed bracket... especially on rough roads.
Watch out for small regulators that screw directly onto tanks - they are often single-stage units intended only for outdoor appliances such as barbecues; an RV regulator should be a two-stage unit, such as that
sold by Scamp.