When i first heard of the blue flash damsel i hadn't even seen one, now i know its just a couple of strands or so of blue krystal flash in an otherwise green damsel fly. 
However, last year i tied up some of these "blue" damsels, its first outing was to Exe Valley fishery, and in the event it proved itself, as numerous fish just launched themselves at it.
Not sure if it was just a one of, or if it would work elsewhere, i tried it out at Hawkridge on the three occasions i have visited, and it seems to work there as well!
So, the tying should you want it is :-
Hook......10 l/shank
Bead.......3.8mm black tungsten
Tail.........2 strands blue krystal flash then Blue marabou then 1 strand b/k/f
Body.......Blue marabou wound round hook (possibly two lots to fill hook shank )
Rib.........silver holographic ( or blue if you have it )


I now have a bright pink version which does " what it says on the.........."
Never be afraid to experiment, it might just save a blank day.

Well, the shoulder/collar bone is a lot better, i think a week resting in the sun on holiday certainly helped. but it nearly didn't, thanks to a complete shambles at Gatwick, check-in was almost non-existant, by the time we got checked in, then through security, we had to run to get to the flight gate, to find that they had taken our luggage of and then had to reload it!! 3 1/2 hours of utter chaos.
Anyway, thats done and dusted, feeling better i decided that i would have a days fishing, and so of i went to Hawkridge reservoir, this is a lovely little reservoir, not too big, and with fish rising, i booked in and had a boat, hardly any wind blowing down the reservoir, so rowed to the dam end, and started my gentle drift, with fish moving all around me i was in my own little heaven. 
When i finally called it a day, i'd lost/missed 4 and landed 5, best a 3 1/2 lb blue.
A great day out.