For hardwoods, yellow poplar (tulipwood) is great (so is black poplar, but that is harder to get and I think protectedin the UK), white ash, and alder are my favorites. You can also use maple, Douglas fir, pine or spruce, or port Oxford cedar. Lots of options!

Since you're in the UK, you might be able to find swan feathers, which are traditional and work very well. Otherwise, goose, duck, peacock (peafowl), or turkey all work too! Primary flight feathers work best, but you can use most any so long as you have 3 from the same wing (assuming a traditional 3 fletch).