John,
Just a suggestion.....but you should probably just say it's this much as the base price in pounds and this much for shipping to the US and this much for shipping to Canada. If postage to Canada is only 8 errrr.....pence?? cents?? more than to the US (1.58 as opposed to 1.50) but I'm paying a total of 10 pounds (which is a little over $20.00 US) compared to those in the States who are paying $16.00 US the math doesn't really work. However, I think the 10 pounds is a more than fair price so I don't mind paying it. I just thought I'd mention that it's likely better to just price in one currency and stay in that currency so you are sure to get the same amount from everyone and your costs etc are covered. Paypal on it's way!