This site should definitely have a health warning on it...
Beware of gorse! Long trousers and sturdy footwear recommended for adults. Gloves might be useful. Small children should wear a long sleeved top etc etc.
I visited Zennor and Sperris and Mulfra in February a couple of years ago...dont remember too much gorse..perhaps I took a different route. The gorse will get you all year round...the bracken is only a problem after about midsummer.