I cycle to work every day and am just glad most of its on bridleway. Havent had any trouble like yours in the past 6 years, my main problem isp eople not seeing me, how can you miss somebody in a high vis jacket, with flashing leds and 2x10 spot lights??
As to carrying something, well you cant carry anything as a weapon, not even for self defence. But you can carry a bike lock, chain and padlock style, wiggle
http://www.wiggle.co.uk/
have some nice ones. I have one in a saddle bag. Main reason is to lock the bike up, but a friend used one in anger on a car.