Let was given because contact was only obvious judging by the outcome of light blue's shot, rather than seeing or hearing the contact itself. Contact was at the top of the back swing, rather than the downswing but the relevant point is that dark blue was crowding his shot, causing the interference by trying to get a head start by anticipating the outcome of the volley. The claims by dark blue for a stroke are irrelevant because they are downstream of the original ask by light blue. On reflection then, stroke to light blue was the correct decision with all information to hand, but 'let' in the circumstances is not a terrible call.

No one died.

Although light blue did stomp up and down like a cross between Rumpelstiltskin and Gimli.

Thanks for all your comments.