A pleasure, Stanley. Now, the yellow-leaved thing can have many causes that are related to nutrient deficiencies. Sometimes the nutrients are there, but there's another problem that prevents uptake.

Is the rest of your garden growing strongly?

I had this on a number of plants when we bought this house two years ago - the garden had been neglected for many years. Rather than try to pinpoint which nutrient is missing, do you have a good compost available? Try to mulch round the plant and see what affect that has.