Trying to identify my Armstrong bicycle

It looks a lot like this Armstrong

The seat stay bolted to the seat tube may be one difference.

Based on the conversation in the thread...

this model is a 1953 so the rear hub tells me

If your bike does have a Sturmey Archer three speed hub you may be able to date the bike by the markings on the hub.

Hub Date Marks – How Old Is Your Sturmey Archer Hub?

Hubs after World War 2 From 1947 to 2000 Sturmey Archer clearly marked their hubs with a date. This hub date marking will show the last two figures of the year and the month.

The article goes on to explain how to date older SA hubs.

Here is the 1950 Armstrong catalog.
This picture looked to me like a good match

Three speeds and dynamo hubs were offered as an option

Other Armstrong catalogs