Grizzly,
I don't know what the weather is like in Somerset, but here in Hbg, the weather turned a bit warm and humid with a light shower every now and again. To my mind, this is a perfect time to try an ant! The warm weather keeps 'em active and the rain knocks them in the creek.
Buggers are worth trying all the time, everywhere. They are as likely to catch a trout as any other fly in your box, even if a blizzard hatch of caddis and sulphurs are coming off as the Green Drake spinners are coming back to the water... even then... don't rule out a bugger. I think the beadheads can be more effective because of the flash as you say, but they will also sink a little more (or a little more quickly) because of the additional weight.
Padraic