MCA
I have just bought an Alpha Eagle helmet and I can tell you the prices are as follows:
Standard helmet £975 + VAT (inc. headset, clear & dark visor, US NATO plug, Coiled lead & Boom mic)
ANR £320 + VAT
ANR Battery box £95 + VAT
Yellow visor (instead of clear) About £50-60 + VAT I think???
Not cheap, but definitely worth it!
I bought mine from Headset Services Ltd at Shoreham Airport
http://www.headsetservices.com/ Speak to Mark Panton.
If you opt for a standard colour, you are more likely to get one quicker. I opted for white which they have in stock. Otherwise it is about an 8 week wait. If you have ANR, it takes about 2 weeks for the ANR to be fitted etc.
Hope this helps and if you want to ask anything else, feel free to PM me...
PMR