Wanted: Tiny frame/bike for midget/umpalumpa other half

went to cavendish and they are ordering in the IRO Mark V HD for me to take a look at, apparently a full custom build will cost around £700, is this worth it?

yes, especially when you're buying a bike that's definitely will be reliable (especially from a trustworthy shop) and fit you nicely without paying a lots of money for a custom-made frame.