update from select

Hi folks,

don't know if it's cos of the 17 hours I've just worked (sympathy vote please) 
but I can't get this one worked out

I've got table names with nid as name id field and nallowfollow flag.
I've got a vehicles table with vowner pointing at nid and a vallowfollow 
field.

How can I update nallowfollow from the appropriate vallowfollow flag?
-- 
Gary Stainburn
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