Russian Arctic convoys

I wonder if anyone can help me.

I am trying to trace whether my late father [John Purdie, CPO, ERA, Service # P/MX 54375] sailed on one of the Arctic convoys. The list of ships on which he served (during the time the convoys were running) shows that two of his ships definitely went on a convoy, namely Argus in '41 and Dido in '44, but his records show that he left both ships prior to their involvement in the convoys. He told me of the atrocious weather and when he was allowed ashore that the children, to whom he gave his 'nutty ration' wouldn't look at him, but were willing to accept the chocolate.

I am also somewhat puzzled regarding his time at/in Spartiate - which I believe was a 'stone frigate' for Western Approaches, Scotland. The records show that the 'tender' was Boston, which also crops up under Boscowan [shore establishment in Dorset] and finally the Nile [shore establishment in Egypt] where, once again, the 'tender' is Boston. I believe that HMS Boston was a small mine-sweeper of around 600 tons, so it appars that my father spent some 19 months attached to her.

I have searched various sites without finding links between ships and dates, so any suggestions will be very welcome. The * denotes shore establishments

Ship [including tender]FromTo
ArgusOct '39Sept '40
Victory*Sept '40Dec '40
Spartiate* [Boston]Dec '40Jan '42
Boscawen* [Boston]Jan '42Deb '42
Nile* [Boston]March '42Aug '42
DidoAug '42June '43
Victory*June '43July '43
Saker* USAJuly '43Jan '44
Pem IV*? [Redmill]Jan '44May '44
Eaglet* [Mermaid]May '44Aug '44
Orlando* [Mermaid]Sept '44Oct '44
Victory*Oct '44Feb '45