Michael Woods writes about I've Made Out a Will

In another sonnet taken from Book of Matches, Armitage writes in the voice of someone who has resolved, by making a will, to donate all his organs, save his heart to the National Health Service. Since this is legally binding, he is clearly in earnest.

Body parts are humorously described interchangeably with engine parts, foods and clock mechanisms. The brain is self deprecatingly “a loaf”. We are familiar with the heart as a “ticker” and we are presented with a welter of other body parts compared to other things. The blood is “a gallon of bilberry soup”, the skeleton a “chassis or cage or cathedral of bone” (lines 6-7)

The persona’s repeated insistence that his heart should be left alone “but not the heart” (line 8) and “but not the pendulum” (line 13) is emphatic. It seems that he may see the heart in a traditional way as the repository of feeling. Alternatively, it may just be an act to deliberately withhold the most sought after organ for transplant. So, in seeming to be entirely magnanimous, the speaker may not be rather curmudgeonly in life and one suspects that he will be so in a posthumous sense, too.