Ah I did not catch your specific setting date, I was just looking at the kit. As you say, a bit early for the RWF.
I am unsure if the Brits had the same plans as us Yanks but we intended to fight in the sewers if we survived the initial onslaught. That or put on civilian clothes and hide among the civilian population if it came to that. At least that was what us lower ranked enlisted grunts thought at McNair Barracks. I spent 4 months on exchange with the RWF but did not learn much about their battle plans in that time, focusing more on exchanging individual infantry skills and drinking beer.
My memory is not what it used to be and it was a long time ago but there was a saying we used to have, something like “Many thought we would only last 3 hours. We figured 3 days. We hoped to last three weeks which would delay enough troops long enough to help units in the West. If we could hold out 3 months we would have won the war.” Something like that.
Also… “Berlin… the worlds largest military POW camp”.