In reply to Rock to Fakey:
As Paul says, Iroko is commonly available in the UK. I actually have some Iroko as a worktop in my kitchen. You can go to any decent hardwood supplier in the UK and buy some. If you want to read around the subject, the wood-database site is great:
http://www.wood-database.com/iroko/
and to show how many different types of Mahogany there are you've got the 'proper' mahogany:
http://www.wood-database.com/cuban-mahogany/
But then other actually different woods, which are also called mahogany:
http://www.wood-database.com/african-mahogany/
It happens a lot, that you get a similar wood passed off as a certain type of wood. It's really odd and something you don't understand unless you're either interested or do wood working. I can rant on about the 'real wood' that Oak Furnitureland sell as well.
I'm honestly not sure why Paul mentions Mahogany on the page to be honest. Seems odd to me. Iroko is often refered to as 'African Teak', so using Teak would be a better word. As my Great Grandad was in the Royal Navy and when he left he retrained as a carpenter, so I actually have a small scrap of what I've been told was teak which he'd apparently got from one of the battleships he'd served on. Teak was used on the decks of the ships back then (specifically the Queen Elizabeth class battleships which he served upon) as it's very hardwearing. Which is why I recommended it as an outdoor finger board.
I've not bought a Crusher board myself, but they do look good. Just as good as the other wooden fingerboards out there, I'm quite sure.