Ah, thank you, John!
I just loaded my in-port career, in Lorient, and transferred to Erprobungs at Danzig. I then selected the new U-boat, the VIIC'42 and took her out for a couple of days. Then I transferred back to Lorient.
Just to make sure, I manually navigated to the H.sie selector in my LSH2015 game folder and checked my H.sie options. I shall give your ideas a whirl with this new patrol.
Thanks again.