I am new to Triathlon and about to do my first event. Borrowing my brothers bike and need to buy a road cycle helmet. Don't want to spend too much on a specialised Tri/ Aero helmet until I decide if this sport is for me. Any recommendations?
You don't need an aero helmet unless you get really seriously into it. I wear an Oakley ARO5 road helmet (they call it aero but it isn't really) for all of my riding (training, commuting, racing) because it is comfy - that is the most important thing.
The Kask Rapido always seems pretty stand out in terms of comfort and price. Beware of buying online though, a couple of the bigger online retailers that you will know have a tendency to sell pretend Kasks (and Giro for that matter) - your local bike shop will maybe be a fiver more than the online price but at least you can be assured that it is genuine. They are about £60 I believe.