Thanks all, for the kind comments. I have to confess that I spent an inordinately long time getting that shot, and if I was not retired, it might never have happened. I took about 330 shots all up, and I can say that getting the timing right is not particularly easy, and requires a lot of trial and error, mostly error.
I have included some of the rejects, the colour shot being taken with a coloured gel over the flash unit. All of these shots were taken with the 100mm macro lens, 1/200 at f13 and an ISO of 400, and flash set to manual with varying flash powers.
My wife expressed the opinion that I was not entirely sane, or words to that effect, and felt that my time could have been better spent doing chores. I ask you, are those the comments of a reasonable person?