The press accounts are muddled with contradiction, misinformation and conjectures written as fact yet from what I can gleam:
In the morning hours of Sat Dec 18, "a few hours" after Jo vanished, a vehicle believed to have been driven by VT and containing the body of Jo was recorded by the CCTV cams crossing the suspension bridge. It had been snowing lightly and continued to snow all night.
This would suggest that the car question crossed in the "wee hours" i.e. perhaps 12-3 AM. In light of the bad weather, I would guess very few vehicles crossed during those hours. Certainly every registered owner (whose tags could be read) were contacted and asked to account for themselves that night. Presumably all but one would have had an explanation that could be verified. Probably the most common account would be "driving home to the eastern suburbs from a social engagement in Bristol". I would expect anyone who LIVED in the vicinity of Clifton would raise an eyebrow since they would be driving away from home at an odd hour during a bad time for driving. If that person were the immediate neighbor of Jo, it should have set of bells and whistles. If the owner reported that they had lent the car to a neighbor of Jo's; the same reaction.
For this reason, giving the police the benefit of any doubt, the owner of the vehicle must have managed to give a very convincing lie. If VT owned the vehicle (which I doubt), he must have worked out something very good. Possibly, VT asked the owner to lie for him on the pretence that "he had nothing to do with the crime but he was afraid that 'involvement' might jeopardize his job, get him deported, whatever.
It is also possible that it took a while to locate the owner; because she was in Chile or something. It should all come out soon enough.
I don't have a clear idea how visible the body was but 5 inches of snow could probably conceal a body pretty well. It is very likely that it was "dumped" that night and not discovered until the snow had melted some.
It is unusual but not unprecedented that an otherwise respectable, law abiding type would do a murder like this. I really hope they aren't jumping into this to fast (like they did with CJ).