Hi Roof,
I've never heard of Simnel cake so had to look it up on Google - looks delicious:-)
I had similar problems with finding the 37 and it took a few attempts before I eventually got the right number - I was invariably 1 or 2 short!
10d - I don't think I'm giving too much away by saying the thematic pair are the final two letters and it creates a word meaning "a dry sausage of partly cooked meat" - but, again, I'd never heard of it (this would be a fitting epitaph for me!)