Hi rocky....Sorry I missed you for a quickie in Tesco's.
Anyway, whilst a bit late perhaps,...Chilli powder can be used as a replacement for Cayenne Pepper, from which Chilli powder is made. Cayenne is hotter than Chilli; which has been 'softened' by the addition of other ingredients , such as garlic,paprika etc.
In place of Fennel you can use Dried Dill, Celery, onion, and/or garlic.
I am yet to find anywhere that sell 'blades of mace'. Mace is the waxy outer covering of the Nutmeg and is bought as a dry powder (blade mace) and looks and smells like ground Nutmeg; which can be used to substitute Mace.
I get the feeling that you are cooking a very tasty dish. If it's for this evening, I shall have to decline any invite which you might give to me, because I had a tooth taken out this morning. Anyway, I would be interested to know what is the meal you are preparing.
Hans.