I've just discovered that the next letter I have in the pile containing those I wrote from the UK to NZ in 1970 was written in December 1970. The ones following that are equally spasmodic. This doesn't mean I suddenly stopped writing; it just means that I probably have the letters written between March 1970 and December in another place. In fact, I've just hauled out a huge pile of letters from another part of the house: there may be a couple of hundred letters here. Not all of them were written by me to my mother; I've already found some from relatives and friends.
So my next task is to sort these into some sort of order. So far there have been several from the time when I toured around NZ with the NZ Opera Company. Plainly they'll have to be dealt with separately to the English ones.
I'll blog again when I've done the sort-out!