When I was looking for one for my bell tent I found the Frontier stoves to be rubbish, just very poor quality tin plate. Take a look at these which are much better quality and value although heavier due to the thicker properly welded plate:
I don't know about the Ozpig, but the Frontier stoves are overrated. I have one. It's great for Occupational Therapy, or if you have nothing else to do but stoke it, fettle it and generally try to keep it going. Hungry for fuel and a pain to clean and repack without getting filthy. Environmentally-aware fellow campers get grumpy if it's smoky.
On the plus side, it'll provide a nice cosy interior to a screened awning and in the depths of a Highland winter, this is GOOD. Rest of the time...And the water heater add-ons that wrap around the flues are an expensive gizmo - you don't need one. Sit a kettle on the top and it'll keep it just off the boil all day, if you have nothing better to do.
I replaced the flue sections with a flexible exhaust pipe which allows me to feed the smoke out of a suitably insulated hole in the side of my awning without paying a fortune for those natty accessories. If you have a roof tent, be aware of where the smoke might blow. Useless for cooking unless heat control isn't important.
I'm not selling ours because The Chef likes the warmth and doesn't mind me having to nurse it .