I traveled in the back of billy today about 30 miles
25°c out ,aircon on, roof fan on, 2 tripes and professor allcock in the back
It stayed coolish but the airflows a bit sh*t because the bulkhead vents under the passenger seat are boxed in by the seat base thing so no flow on that side . bloody ford
So the fan is sucking cold air through the big hole in the bulkhead and mostly just cooling the roof
May have to get the angle grinder out again