Am now in the market for a helmet and have looked at all the responces and can summerise.
Gallet: comfortable and light but noisy
Alpha: Comfortable and light, Quiet but maybe not as durable
Gentex: Trusty old design bulky but very durable.
Think price/ value/options will have to be the decider for me.
At this stage looks like a Gentex from flight suits in USA with all the fruit is the best value so far.