That's simply not the case.
We cannot positively say that Dryland referred to his notes. It doesn't say so.
You are assuming he referred to notes prior to writing the statement, but you do not know that. It's possible that he did, but it's possible that he didn't for any number of reasons.
Your conclusion is a suggestion only, a possibility and nothing more.
It doesn't look like the office was recently decorated/converted.
Sorry Hartley, but it won't work.
1. The police issue firearms certificates and keep records.
2. The police refer to these records.
3. The statement of P.C. Dryland is worded without any form of qualification or caveat whatsoever.
4. If P.C. Dryland wasn't sure, he would either indicate this in his statement or not provide the statement at all. He is clearly relying on a mixture of memory and records, including his own pocketbook and official records. This is reasonable to assume because all police officers do this.
5. If the downstairs office conversion happened prior to 4th. August 1985, then P.C. Dryland is probably lying (for the reasons explained exhaustively earlier in the thread). If after 4th. August 1985, then he may still be lying, but I think we should give him the benefit of the doubt.
I don't mind criticism because sometimes we can all be wrong, but I just think you're being obtuse here and showing a lack of common sense. And I think you're doing this intentionally.
I think the reason you're being like this is because you know that Nevill's poor handling of the firearms, and possible police culpability in this, fits more with a scenario of Sheila as the killer. That's why you're worried.
By the way, I have a copy of Nevill's firearms certificate. It can be downloaded from the Forum.