Not sure if you have found these web pages yet but there is some info on the amp here:-
http://www.vintagehofner.co.uk/britamps/restof.html
http://www.vintagehofner.co.uk/amps/shaft1.html
It looks like they were made early to mid sixties which seems to tie in with the date on the capacitor. Looking at the photos it looks like the speaker is original so I'm sure it will be fine - it seems to have lasted nearly 60 years so far! With a single EL84 it will only be about 5 watts, a lot of small guitar amps from that era used the commonly available radio speakers of the time.