You didn't mention what year your Scamp might be, but there are TWO different Dometic refrigerator versions out there, early and late. The early ones, with the "Square" boiler cover, are very sensitive to beong level and, when they stop working, the "inversion" technique may help, but don't count on it working. It's usually the end for the refrigerator.
Late ones have a curved boiler cover and, while they are less sensitive to being level, can have problems if used drastically out of level. However, the later ones usually self-correct if allowed to cool and are restarted in a level condition. Here's a link to a Dometic publication on that topic, look on Page 45.
Both type share in common the need to clean the LP jet, the burner and the soot from the flame tube. Unfortunately some installations require removing the refrigerator to accomplish some or all of these three steps. See the above link for directions on these steps.
And last, is LP pressure. LP pressure is measured in inches of mercury and takes a special tool for measurement, but most RV dealers, and any Lp dealer, can do this and adjust the regulator if necessary. If your pressure is low you will not get a hot enough flame and cooling will suffer.
These last two, soot in the flame tube and low LP pressure seem to be the leading causes of poor cooling when the electrical
mode works OK.