The midges have been here on and off for a good week or so. I do keep Dolly on brewers yeast, linseed and covered all year round now. So far she seems fine.
Last year she was also relatively OK so long as I kept her covered at all times and applied plenty of Naff Off when we rode etc. and first thing in the morning.
The two previous summers she was so bad I had to resort to giving her steroid jabs, which of course bring other risks, but it worked for us but I am paranoid about keeping her off too much grass because of both the lammi risk and I believe that sweet grass makes her itch more. So last summer no steroids and just the above regime seemed to work fine 99 per cent of the time.
I think it is probably just experimenting with various options to find what works best for your particular horse. Sadly I don't think there is any one sure fire method of dealing with it.