Will a flash reach about 25m though?
I really need to take shots of a panto/production at a local church but i have to be at the back of the room they perform in.
If you really are 25m away then I think you may struggle. The flash will help a bit but you will be mainly using available light.
Any chance of visiting the venue first to see how you get on with available light? Failing that try something that might be similar - shop window display at night?
I have got the FL-50 for my E1 and it seems to be a good flash not quite got to grips with it yet but have had some fairly good results. Glad i bought it over the cheaper olympus flashes.