Harbeth speakers are a natural progression from BBC speakers and Harbeth keep the BBC philosopy alive.
Graham are actually reproducing ( as close as possible ) the BBC models.
The Harbeth M30 and Graham LS5/9 are similar and inevitably people will choose one or the other.

They are addressing different markets in my opinion.
I know the LS3/5a well and listening to the LS3/5 will be very interesting...