tried to get some good pictures of the interior variations.
first, front brace + no guides (doesn‘t have the label guides on the outside), front brace with guides and no front brace with guides.
http://img519.imageshack.us/img519/2552/landroverfire57rwgrlguixq0.jpg
the difference with the side brace and corner pillars.
http://img223.imageshack.us/img223/4306/landroverrw57intpillarzv1.jpg
these also have the two or three braces between wheel wells with round or plastic interior wheel arches.
with small differences on the out side
these have the label/decal side guides with long and short ladder supports, also on the sf versions.
http://img441.imageshack.us/img441/9051/landroverrw57ladderguidsv4.jpg

refuse truck interior base/grill. left picture with supports on both sides of the orange tab and angle supports, right with no supports. both have tow guides.
http://img253.imageshack.us/img253/5259/refusetruckrw7intbrace3qh7.jpg
the rw refuse truck was one of many rw that had the thin and thick black fine tread tires with rounded and straight cut treads.
http://img124.imageshack.us/img124/3284/refusetruckrw7trwidthbt2.jpg
http://img124.imageshack.us/img124/8008/refusetruckrw7trwidth1aho2.jpg

the rw refuse truck was one of many rw that had the thin and thick black fine tread tires with rounded and straight cut treads.

http://img124.imageshack.us/img124/8008/refusetruckrw7trwidth1aho2.jpg
I have noticed these thicker bpw on my no 4 Dodge stake trucks (did it come with thin tyres too?) but not on other trucks commonly found with normal thickness bpw.Thicker tyres improve the look of the 7 - wheels look a bit small given the larger size on the 70 looking just right heightwise if a little thin (70 SF looks just right to my eyes)

all of my stake trucks have the thick size too.
a small quick but not complete list. :)
#14 bedford ambulance (later).
#20 erf every ready with grey plastic.
#13 dodge bp wrecker.
#10 pipe truck.
here is a pipe truck with a combination of sizes, having square and curved cut treads on both thick and thin tires.
http://img363.imageshack.us/img363/4326/pipetruckrw10trsizesi6.jpg