Notwithstanding the answer above, the law is very clear. If you have not received either a positive or negative response (with or without a written explanation) then your application is deemed to be refused.

"Sect 3 (9) A decision on an application for a firearm certificate or its renewal shall be given within 3 months from the date on which the applicant submitted a completed application form."

………..Note the word SHALL not should or anything else……… (my edit)

(10) Where the application is refused, the applicant shall be informed in writing of the refusal and the reason for it.

[Appeal to District Court.

15A.— (1) An appeal may be made to the District Court by a person aggrieved by any of the following decisions made by an issuing person:

(a) to refuse to grant a firearms training certificate under section 2A of this Act;

(b) to refuse to grant or renew a firearm certificate under section 3 of this Act;

(2) An appeal shall be made within 30 days of receipt of notice of the decision concerned.

15A.-(5) For the purposes of this section—

(a) an issuing person—

(i) who is required under section 3(9), 4A(7) or 10(4F) to decide on an application within a specified period, and

*****(ii) who does not so decide,********

is deemed to have decided to refuse to grant the application,

(b) the applicant is deemed to have received notice of the decision on the expiration of that period, and

(c) as the case may be, section 3(10) does not apply in relation to the application.

As the law is written and 3 months has passed, your application is deemed to have been refused (whether you received notification of same or not) and you only have 30 days to appeal this decision to the district court, the 30 days starting on the day your 90 days runs out.

The above is for your information, and it is up to you how you use it