It was a Bed'n'ISA (or a Bed'n'SIPP) - someone moving shares from one account to a tax free account. I've done them myself and they always show up as two trades (one the sell and the other the buy), seconds apart.
i know companies are meant to issue tr1s, but i've a feeling often they don't, and no-one seems to enforce this. i think it sometimes depends upon whether the individual can be ****d to complete one.