It’s not a built up area, but I’m totally confused. Street lighting. Houses. What defines a built up area? It’s always been regarded a 60 limit for public cars and police anyway.
What you’re confusing, I think, is that the legal status of the built-up area (technically “restricted roads”) applies unless the road is signed otherwise.
The relevant bit of law is here:
http://www.legislation.gov.uk/ukpga/1984/27/part/VI
Rule 81 states that a restricted road carries a 30mph limit. 82 defines a restricted road via the lighting as we’ve discussed, unless the responsible local authority decides to override this in which case it requires signage.
Rule 85(5) explains that in your example, the lights and the absence of signs implies that it’s a restricted road as above. So, unless there are signs to the contrary then it would appear as though your locals (and the local plod) all have it wrong and it is in fact a 30mph limit. Which is interesting, I’d have probably interpreted it as 60 too. Gosh.
Going on to Molgrips’ example,
Built-up area, so 30mph (check the lighting) in the absence of any other information. But as he later explained, there are 40mph repeater signs so, of course, that takes precedence.