I couldn't find a way to ship my own bike for less then £700 and a whole load of hassle. 3 days shipping from the UK, although I didn't look at airfreight. I reckon you'd need a good 2+ weeks there to make it worthwhile.
It could be worth it though. The less you rush Iceland the more it pays you back.
Yeah that's the cost I've seen. There's a guy on ukgser that listed out the logistics of his trip and said it was straight forward. Drop bike at Hull, get flight 3 days later, then pick up from Reykjavik docks. To hire a bike for the same 10 days would be 2300euros.
I guess it depends how close to Hull you are - for me it's about 90 mins and I already have a trailer so not too bad