Spadeadam isn't always NOTAMed as active. Any of the local ATC units, or Scottish Info, will confirm its status. It is usually cold at the weekend, but not always
No NOTAM outside AIP hours then it shouldn't be active. The ground equivalent of 'airmanship' surely ??. I've never heard of it being active for anything outside published hours without there being a NOTAM.
It would be MOR'ed if the range authorities did otherwise (and I would be one of the first to do so ;0 ), however the guys down on the range are very switched on and I find it hard to believe they would go against the rules.
British Gas are also meticulous in their NOTAMs. Massive law suit if they weren't and caused an aerial accident
The lesson learnt always talk to the range controller, they are the only one to really know if its Hot or Cold.
Semantics, I know, but Newcastle can only give you a DAAIS and not a crossing service. For DACS, the published frequency is Spadeadam. Better safe than sorry ... as you found out