Funnily enough I had the same situation, though it was 3 months after the new boots to get a puncture.
700 notes though, you don't drive an '08 Vectra by any chance. I remember a mate of mine getting one of those and the daft size of the alloys meaning it cost him 800 quid to do. I rember him saying something like if they were half an inch wider or narrower (either way) it would have halved the cost of the tyres as it'd put him towards a common size.
Mondeo Zetec-S its got stupid low profile tyres on it 225/40/18, it eats them! cheapos don't last 5mins. Have to agree with your mate if I have 17" ones would half the price!