Hi Spatenman - to be honest I think you would have to ask revenue for an interpretation as I'm not sure that they have hard and fast rules for all financial instruments and there are anomolies - for example with options. However I suspect you are on the right track as I don't see how they could apportion any of the gain as "income" rather than "capital gain". If this were the case, you should take it to the extreme and go with zero coupon bonds, if you can find ones with a suitable term; you'd avoid income tax completely and just get hit by capital gain when you sell.
However, I've no authority in this area. Because of tax treatment, hardly any individuals buy them here (unlike in the US where municipal, state and federal bonds are tax-free). You'd really need confirmation from revenue and/or a tax advisor/accountant that zeros only attract CGT.