thanks a bunch, loge - relieved my misery and restored the symmetry ...
I had a mistake in 21 which was leading me to a different sort of uselessness. Well, that was a labour of love, if hours rather than Hamish Soup's (presumed) many days ... still, I guess he gets paid for it, however little, judging by my own Guardian contributions. But it was worth the effort, Hamish. Well done - again.