Torpedoes and Tides Scenario - Achtung Minen!

I've been scribbling some outline notes for a Torpedoes and Tides scenario set in May 1942. This involves a minelaying sortie by a rotte of two S-38 boats of the 4th S-Boote Flotilla, based in Boulogne, in the convoy lanes off Dungeness. A patrolling Isles class trawler, HMS Sir Galahad, is in the area and bumps into the enemy E-boats, who must sink her or force her to retreat, then evade back to their base, scoring set victory points for doing so. The trawler has to batter, wreck or force off the two enemy boats before being sunk, scoring cumulative points for the damage inflicted. 

There will be fog patches and a partial moon to add a bit of tactical shenanigans, while the E-boats will have zero torpedo reloads, being lightened for the minelaying sortie, so once expended they'll be down to guns only. I expect the trawler will go down fighting but as long as enough damage is inflicted on the E-boats to disrupt the mine laying mission, there's a chance it won't be a walkover for the Kriegsmarine, assuming I balance the victory points properly? 

One of the S-boote, S-55, will be C2 as it was the highly experienced CO, Götz Freiherr von Mirbach's boat, while the trawler commander and crew will also be C2 to give her a fighting chance. I'm not sure if the mine laying task will actually have to be carried out, as that would complicate things and be a bit unlikely, but it's still a work in progress and may be tweaked a bit. It will be interesting to see how it plays out, when I get round to it, and if I will need to beef up the RN or not by using a more powerful escort like a destroyer or corvette.